Paper, image-recording material support, and image-recording material

ABSTRACT

Paper and an image-recording material support which have high surface planarity and excellent gloss are disclosed. Moreover, an image-recording material is disclosed which uses the image-recording material support and is capable of obtaining high quality image. The paper includes raw paper. The paper satisfies at least one of the following conditions (i) and (ii): (i) the paper has an inner bonding strength of 160 mJ or more specified in Japan Technical Association of the Pulp and Paper Industry No. 54, and an average center surface roughness (SRa) on at least one face of the paper is 0.9 μm or less at a cutoff wavelength of 0.3 mm to 0.4 mm, and (ii) an Oken type smoothness S (second) on the at least one face of the paper, and a density ρ (g/cm 3 ) of the paper satisfy an expression S 1/2 /ρ 3 ≧15.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to paper having high surface planarity andexcellent gloss. Moreover, the present invention relates to paper, animage-recording material support and an image-recording material whichare preferably used for an electrophotographic material, a heatsensitive material, an inkjet-recording material, a sublimation transfermaterial, a silver salt photographic material, a heat transfer material,and the like.

2. Description of the Related Art

Conventionally, raw paper, synthetic paper, synthetic resin sheet, coatpaper, laminate paper, and the like are well known as a support forvarious image-recording materials such as an electrophotographicmaterial, a heat sensitive material, an inkjet-recording material, asublimation transfer material, a silver salt photographic material, aheat transfer material, and the like. The above image-recordingmaterials are used for image-recording so as to obtain an image printhaving high quality and high gloss. For this purpose, high planarity isneeded for the above image-recording materials, which also involvesnecessity for high planarity of the support therefor.

For satisfying the above, various proposals have been made. JapanesePatent Application Publication (JP-B) No. 06-55545 discloses animage-recording material support formed with an intermediate layer(containing a white pigment) on raw paper (containing a polyolefinsynthetic pulp) having a density of 0.8 g/cm³ to 1.0 g/cm³. JapanesePatent Application Laid-Open No. 11-11004 discloses an image-recordingmaterial support having its inner bonding strength in a range from 0.9kg·cm to 2.2 kg·cm and having its friction coefficient in a range from0.6 to 1.2. JP-A No. 2001-301098 discloses an image-recording materialsupport having its average center surface roughness (SRa) of 0.75 μm orless measured at a cutoff wavelength of 5 mm to 7 mm. Moreover, JP-B No.2671154 discloses an image-recording material support having pulp'saverage degree of polymerization of 800 or more and having an innerbonding strength (of raw paper) in a range from 1.0 kgf·cm to 2.0kgf·cm, and having pH (of face of raw paper) of 6.0 or more.

When the image-recording material support has low strength, use of theimage-recording material having the support for recording an image maycause a curl to an image print which is outputted from a printer. Inaddition, the image-recording material support having low planaritycannot form an image that has high-quality and high gloss. Moreover, rawmaterials of the above image-receiving material support are naturalpulps such as needle-leaf tree (hereinafter, when necessary, referred toas “needle-leaf tree pulp”), broad-leaf (hereinafter, when necessary,referred to as “broad-leaf tree pulp”), and the like, which are to beproduced by drying wet paper with a manual paper-making machine. Theimage-recording material support thus produced may result indeteriorated planarity which is attributable to shrink of pulp fiber ofthe natural pulp (raw material) during the drying.

Any of the proposals disclosed in the above publications cannot solvethe problems sufficiently. Such an image-recording material support isnot proposed yet as having high planarity and extremely excellent gloss.In addition, such an image-recording material is not proposed yet ashaving a support therefor, having high-quality image and excellent glossafter image-recording, having high rigidity (stiffness), and causing asmall curl. Developments of the above are desired.

Conventionally, paper that is efficiently machined at high speed isdried between many cylindrical driers by receiving a tension in thelongitudinal direction (paper-making direction) while causing freeshrinkage in the lateral direction. When being subjected to a change inhumidity, the thus machined paper is likely to cause a large extensionand/or shrinkage (telescopic motion) in the lateral direction. Withthis, recordings such as photographing with the above paper as a supportmay increase curl in size, thus high-quality image cannot be formed.

To solve the above problem, JP-A No. 01-292354 (equivalent of JP-B No.2739160) discloses an electrophotographic transfer paper having a smallshrinkage factor, an excellent surface smoothness, and causing a smallcurl, even when the paper is subjected to a humidity change afterdrying. Specifically, the above electrophotographic transfer paper ismachined with so-called a Yankee paper machine that can control dryingshrinkage both in the longitudinal and lateral directions, withoutreceiving a longitudinal tension during drying.

In this case, however, using the Yankee paper machine may generallyrestrict many paper-making conditions such as freeness of pulp papermaterial, paper-making speed, and the like.

On the other hand, a treatment in which a sheet of paper is dried whilebeing pressurized (hereinafter may be referred to as press drytreatment) is expected to provide higher strength, elasticity modulus,density and the like, and such process is currently under development(Takuya Kadoya et al., Seishi Kagaku “Science of paper-making” (Tokyo:Chugai Sangyo Chosakai, 1982), pp. 174-177), Jun. 30, 1982 (Showa 57).In addition, JP-A No. 2000-500536 and JP-A No. 07-91829 (JP-B No.3041754) propose web pressure drying apparatuses which perform heatdrying of a fiber web with a press dry treatment and provide lessrestrictions when used in a manufacturing line. In the aboveconventional technologies, however, no specific press drying conditionsand the like are disclosed. JP-A No. 2000-500536 and JP-A No. 07-91829(JP-B No. 3041754) only disclose the press drying apparatuses, with nodescriptions about relation between the press drying treatment andimage-recording material support.

On the other hand, conventionally, raw paper, synthetic paper, asynthetic resin sheet, coat paper, laminate paper, and the like are wellknown for use as an image-recording material support. Among these, thecoat paper and the laminate paper are preferable.

Methods of producing the coat paper and the laminate paper comprise asolvent coating method of applying to raw paper a thermoplastic resinwhich is solved in an organic solvent, an aqueous coating method ofapplying to raw paper a thermoplastic resin which is made into a latexor an aqueous solution (varnish), a dry laminate method of athermoplastic resin, a melting extrusion coating method, and the like.

However, the above solvent coating method that uses a harmful organicsolvent may cause harmful effect on the environment. In the aboveaqueous coating method, water may swell the raw paper when the latex orthe aqueous solution (varnish) is applied to the raw paper, thus losingsmoothness of the raw paper, which is so called a “return.” Moreover,the aqueous coating method is not applicable to resins which are lesslikely to be made into latex or aqueous solution.

Summarizing the above, such an image-recording material support and animage-recording material are not proposed as having high surfacesmoothness and extremely excellent gloss, leaving an issue of furtherimprovement and development.

It is therefore an object of the present invention to provide paper andan image-recording material support which have high planarity andexcellent gloss. It is another object of the present invention toprovide an image-recording material which has high-quality image andhigh gloss after image-forming, and causes a small curl.

SUMMARY OF THE INVENTION

Under the present invention, a paper according to its first aspectcomprises a raw paper. The paper satisfies the following: the paper hasan inner bonding strength of 160 mJ or more specified in Japan TechnicalAssociation of the Pulp and Paper Industry No. 54, and an average centersurface roughness on at least one face of the paper is 0.9 μm or less ata cutoff wavelength of 0.3 mm to 0.4 mm.

As a result, the paper according to its first aspect having the innerbonding strength and the average center surface roughness (SRa)respectively in the above certain ranges can have high surface planarityand can be used preferably for an image-recording material support.

Under the present invention, a paper according to its second aspectcomprises a raw paper. The paper satisfies the following: an Oken typesmoothness S (second) on the at least one face of the paper, and adensity ρ (g/cm³) of the paper satisfy an expression S^(1/2)/ρ³≧15.

As a result, the paper according to its second aspect satisfying thatthe Oken type smoothness S and the density of the paper satisfy thefirst expression can have high surface planarity and an extremelyexcellent gloss and can be used preferably for the image-recordingmaterial support.

Under the present invention, an image-recording material supportaccording to its first aspect comprises a paper which comprises a rawpaper. The paper satisfies at least one of the following conditions (i)and (ii): (i) the paper has an inner bonding strength of 160 mJ or morespecified in Japan Technical Association of the Pulp and Paper IndustryNo. 54, and an average center surface roughness on at least one face ofthe paper is 0.9 μm or less at a cutoff wavelength of 0.3 mm to 0.4 mm,and (ii) an Oken type smoothness S (second) on the at least one face ofthe paper, and a density ρ (g/cm³) of the paper satisfy an expressionS^(1/2)/ρ³≧15.

As a result, the image-recording material support according to its firstaspect can have high surface planarity and an extremely excellent glossand can be used preferably for the image-recording material.

Under the present invention, an image-recording material supportaccording to its second aspect comprises a raw paper subjected to apress dry treatment; and a coat layer. The coat layer is made bysubjecting a face of the raw paper to a surface treatment using a memberwith a smooth surface, the face of the raw paper being to be formed withan image-recording layer.

With the press dry treatment, density, elasticity modulus, tensilestrength, strength and the like can be improved. Moreover, a base paperwhich was subjected to the press dry treatment is formed with the coatlayer, and the coat layer is allowed to abut on the smooth surface, fortransferring the surface appearance.

As a result, the image-recording material support according to itssecond aspect can have high surface planarity and an extremely excellentgloss.

An image-recording material under the present invention comprises asupport; and an image-recording layer disposed on the support. Theimage-recording material uses, as the support, the image-recordingmaterial support according to at least one of its first aspect and itssecond aspect described above.

As a result, high-quality image can be provided for the image-recordingmaterials for any of the applications including an electrophotographicmaterial (electrophotographic image-receiving material), a heatsensitive material (heat sensitive coloring recording material), aninkjet-recording material, a sublimation transfer material (sublimationtransfer image-receiving material), a silver salt photographic material(silver halide photographic photosensitive material), and a heattransfer material (heat transfer image-receiving material).

Further objects, features and advantages of the present invention willbecome apparent from the following description of the preferredembodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic of an example of a press dry treatmentapparatus under the present invention.

FIG. 2 shows a schematic of an example of a press dry treatmentapparatus used for a production line under the present invention.

FIG. 3 shows a schematic of an example of a wet cast method under thepresent invention.

FIG. 4 shows an example of a gelatinization cast method under thepresent invention.

FIG. 5 shows an example of a rewet cast method under the presentinvention.

FIG. 6 shows a schematic of a fixing belt apparatus of a printer usedfor examples under the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(Paper)

Under the present invention, a paper according to its first aspectcomprises a raw paper. The paper has an inner bonding strength of 160 mJor more specified in Japan Technical Association of the Pulp and PaperIndustry (hereinafter referred to as “JAPAN TAPPI”) No. 54, and anaverage center surface roughness (SRa) on at least one face of the paperis 0.9 μm or less at a cutoff wavelength of 0.3 mm to 0.4 mm.

The inner bonding strength is the one that is specified in JAPAN TAPPINo. 54.

As long as being 160 mJ or more, the inner bonding strength is notparticularly limited, and can be suitably selected according to theobject. For example, the inner bonding strength is preferred to be 200mJ or more, and more preferably 216 mJ or more.

The average center surface roughness (SRa) can be obtained by scanningthree-dimensionally a plane having a certain roughness, and therefore isdifferent from an average center line roughness (Ra) that can beobtained by scanning a linear roughness of a plane. As the roughness atthe cutoff wavelength of 0.3 mm to 0.4 mm decreases, the surface mayappear flatter and flatter. An apparatus for measuring the averagecenter surface roughness (SRa) is not particularly limited, and can besuitably selected according to the object. For example, SURFCOM 570A-3DF(made by Tokyo Seimitsu) can be used for measuring the average centersurface roughness (SRa) at the cutoff wavelength of 0.3 mm to 0.4 mm,based on the following measuring condition and analysis condition.

—Measuring Condition and Analysis Condition—

Scanning direction: MD direction of sample.

Measuring length: Machining paper direction (X-direction) 50 mm, andperpendicular direction (Y-direction) thereto 30 mm.

Measuring pitch: X-direction 0.1 mm, Y-direction 0.1 mm.

Scanning speed: 30 mm/sec.

Band pass filter: 0.3 mm to 0.4 mm.

Herein, as long as being 0.9 μm or less at the cutoff wavelength of 0.3mm to 0.4 mm, the average center surface roughness (SRa) is notparticularly limited, and can be suitably selected according to theobject. For example, the average center surface roughness (SRa) ispreferred to be 0.8 μm or less, and more preferably 0.75 μm or less.

As long as the average center surface roughness (SRa) is satisfied on atleast a first face of the paper, it is not particularly limited. Whenthe paper is used as an image-recording material support, however, theaverage center surface roughness (SRa) is to be preferably satisfied onthe side (of the image-recording material support) to be formed with animage-recording layer.

Under the present invention, a paper according to its second aspectcomprises a raw paper. An Oken type smoothness S (second) on at leastone face of the paper, and a density ρ (g/cm³) of the paper satisfy anexpression S^(1/2)/ρ³≧15.

Hereinafter, the value calculated by the above expression S^(1/2)/ρ³are, as the case may be, referred to as “H index.”

The Oken type smoothness S (second) is defined based on the method B(measuring method) specified in JAPAN TAPPI No. 5, and is obtained forexample, by a smoothness (roughness) test using an Oken type smoothnessair-transparency tester.

As long as the above is satisfied, the Oken type smoothness S (second)is not particularly limited, and can be suitably selected according tothe object. For example, the Oken type smoothness S is preferred to be100 sec or more, and more preferably 150 sec or more. An upper limit ofthe Oken type smoothness S is not particularly limited, ordinarilypreferred to be 600 sec or less, and more preferably 500 sec or less.

A face having the Oken type smoothness S (second) satisfying the abovecan be only on one side of the paper, or on both sides of the paper.When the paper is used as an image-recording material support, however,the Oken type smoothness S (second) is preferably satisfied on the sideto be formed with an image-recording layer, from the viewpoint offorming high-quality image.

As long as the above is satisfied, the density ρ (g/cm³) is notparticularly limited, and can be suitably selected according to theobject. For example, the density ρ (g/cm³) is preferred to be 0.85 g/cm³to 1.05 g/cm³. The density less than 0.85 g/cm³ may cause insufficientplanarity, and more than 1.05 g/cm³ may cause an insufficient rigidity(stiffness).

As long as being 15 or more, the H index calculated by the aboveexpression S^(1/2)/ρ³ is not particularly limited and can be suitablyselected according to the object. For example, the H index is preferredto be 16 or more, and more preferably 17 or more. The H index less than15 may cause an insufficiency to at least one of the planarity and therigidity (stiffness). An upper limit of the H index is not particularlyspecified, and can be suitably selected according to the object. Forexample, the upper limit of the H index is preferred to be 23 or less,and more preferably 19 or less.

Moreover, an Oken type smoothness S₁ (second) on a face of the paperthat is subjected to a press dry treatment, and a density ρ₁ (g/cm³) ofthe paper after the press dry treatment satisfy an expression S^(1/2)/ρ₁³≧15.

The paper is not particularly limited, and can be suitably selectedaccording to the object. For example, the paper can be raw paper,synthetic paper, a synthetic resin sheet, coat paper, laminate paper,and the like.

The above raw paper is not particularly limited, and can be suitablyselected according to the object. Specifically, the raw paper can bepreferred to be those described on page 223 to page 224 of Society ofPhotographic Science and Technology of Japan “Fundamentals ofPhotography (shashin kougaku no kiso)—Silver Salt Photograph” publishedby Corona (Showa 54 [1979]).

As long as being a known material used for the support, the raw paper isnot particularly limited, and can be suitably selected according to theobject. Examples of the raw paper include natural pulps such asneedle-leaf tree pulp, broad-leaf tree pulp and the like, a mixture ofthe above natural pulp(s) with a synthetic pulp(s), and the like.

The pulp usable for a raw material of the raw paper is preferred to bethe broad-leaf tree pulp, from the viewpoint of simultaneously improvingplanarity, dimension stability and the like of the raw paper, in a goodbalance and to a sufficient level. The needle-leaf tree is, however,also usable.

Examples of the broad-leaf tree pulps include broad-leaf tree bleachedkraft pulp (LBKP), broad-leaf tree sulfite pulp (LBSP) and the like.Among these, the broad-leaf tree bleached kraft pulp (LBKP) ispreferable.

A content of the broad-leaf tree pulp relative to the paper is notparticularly limited, and can be suitably selected according to theobject. For example, the content is preferred to be 50% by mass or more,more preferably 60% by mass or more, and still more preferably 75% bymass or more.

Examples of the needle-leaf tree pulp include needle-leaf tree bleachedkraft pulp (NBKP) and the like.

As the above pulp, it is preferable to use mainly a broad-leaf tree pulpthat originally has a short fiber length.

A beater, a refiner or the like can be used for beating the pulp. Whennecessary, various types of additives can be added to a pulp slurry(hereinafter referred to as “pulp paper material” as the case may be)which can be obtained after beating the pulp. Examples of the additivesinclude filling material, dry paper reinforcer, sizing agent, wet paperreinforcer, fixing agent, pH regulator, other agents and the like.

Examples of the filling materials include calcium carbonate, clay, whiteclay, kaolin, white earth, talc, titanium oxide, diatomaceous earth,barium sulfate, aluminum hydroxide, magnesium hydroxide and the like.

Examples of the dry paper reinforcers include cationic starch, cationicpolyacrylamide, anionic polyacrylamide, amphoteric polyacrylamide,carboxy-modified polyvinyl alcohol and the like.

Examples of the sizing agents include rosin derivatives such asaliphatic salts, rosin, maleic rosin or the like; paraffin wax, alkylketene dimer, alkenyl succinic anhydride (ASA), epoxy aliphatic amide,and the like.

Examples of the wet paper reinforcers include polyamine polyamideepichlorohydrin, melamine resin, urea resin, epoxy polyamide resin andthe like.

Examples of the fixing agents include polyfunctional metal salts such asaluminum sulfate, aluminum chloride, or the like; cationic polymers suchas cationic starch, or the like.

Examples of the pH regulators include caustic soda, sodium carbonate andthe like.

Examples of other agents include defoaming agents, dyes, slime controlagents, fluorescent whitening agents and the like.

Moreover, softeners can also be added when necessary. For the softeners,ones which are disclosed on pp. 554-555 of Paper and Paper TreatmentManual (Shiyaku Time Co., Ltd.) (1980) and the like can be used, forexample.

Each of the above additives and the like can be used either alone or incombination of two or more. The amount of each of the additives into thepulp paper material is not particularly limited, and can be suitablyselected according to the object, 0.1% by mass to 1.0% by mass ispreferred ordinarily.

Moreover, the pulp paper material which is the pulp slurry to which thevarious types of additives are added if necessary is to be machined byusing paper-making machines such as a manual paper-making machine, along-net paper-making machine, a round-net paper-making machine, atwin-wire machine, a combination machine, and thereafter is dried forpreparing the raw paper. When necessary, either before or after thedrying, a surface sizing treatment can be carried out.

Examples of surface sizing treatment liquids used for the surface sizingtreatment include at least one metal salt selected from alkaline metalsalt and alkaline earth metal salt, water-soluble high molecularcompound, fluorescent whitening agent, waterproof substance, pigment,dye and the like.

As the at least one the metal salt selected from the alkaline metal saltand the alkaline earth metal salt, those described above can be used.

The water-soluble high molecular compound is not particularly limited,and can be suitably selected according to the object. Examples of thewater-soluble high molecular compounds include polyvinyl alcohol,carboxy-modified polyvinyl alcohol, carboxymethyl cellulose,hydroxyethyl cellulose, cellulose sulfate, polyethylene oxide, gelatin,cationic starch, casein, sodium polyacrylate, sodium salt ofstyrene-maleic acid anhydride copolymer, sodium polystyrene sulfonateand the like. Among these, polyvinyl alcohol, carboxy-modified polyvinylalcohol, carboxymethyl cellulose, hydroxyethyl cellulose, cellulosesulfate, polyethylene oxide, and gelatin are preferable, andparticularly polyvinyl alcohol (PVA) is more preferable.

A content of the water-soluble high molecular compound is preferably 0.5g/m² to 2 g/m².

Examples of the fluorescent whitening agents include stilbene compounds,coumarin compounds, biphenyl compounds, benzo-oxazoline compounds,naphthalimide compounds, pyrazoline compounds, carbostyryl compounds,carbostyryl compounds, diamino stilbene disulfonic acid derivative,imidazole derivative, coumarin derivative, triazole derivative,carbazole derivative, pyridine derivative, naphthalic acid derivative,imidazolone derivative and the like. Among these, stilbene compound ispreferable.

A content of the florescent whitening agent is not particularly limited,and 0.01% by mass to 0.5% by mass is preferable, more preferably 0.02%by mass to 0.2% by mass.

Examples of the waterproof materials include latex emulsions such asstyrene-butadiene copolymer, ethylene-vinyl acetate copolymer,polyethylene, vinylidene chloride copolymer or the like; polyamidepolyamine epichlorohydrin and the like.

Examples of the pigments include calcium carbonate, clay, kaolin, talc,barium sulfate, titanium oxide and the like.

As for the above-mentioned raw paper, to improve the rigidity(stiffness) and dimension stability of the image-recording materialsupport, it is preferred that the ratio (Ea/Eb) of the longitudinalYoung's modulus (Ea) to the lateral Young's modulus (Eb) is within arange from 1.5 to 2.0. When the ratio (Ea/Eb) is less than 1.5 or morethan 2.0, the rigidity (stiffness) and dimension stability of theimage-recording material support tend to deteriorate, and may causeinconveniences to traveling property during transportation.

It has been found that, in general, the “rigidity (stiffness)” of thepaper differs based on differences in the way the paper is beaten, andthe elasticity modulus of paper from paper-making after beating can beused as an important indication of the “rigidity (stiffness)” of thepaper. The elasticity modulus of the paper can be calculated from thefollowing equation by using the relation of the density and the dynamicmodulus which shows the physical properties of a viscoelastic object,and by measuring the velocity of sound propagation in the paper using anultrasonic oscillator.E=ρc ²(1−n ²)

where “E” represents dynamic modulus; “ρ” represents density; “c”represents the velocity of sound in paper; and “n” represents Poisson'sratio.

As n=0.2 or so in a case of ordinary paper, there is not much differencein the calculation, even when the calculation is performed by thefollowing equation:E=ρc²

Accordingly, when the density of the paper and acoustic velocity can bemeasured, the elasticity modulus can easily be calculated. In the aboveequation, when measuring acoustic velocity, various instruments known inthe art may be used, such as a Sonic Tester SST-110 (Nomura Shoji Co.,Ltd.) or the like.

The thickness of the raw paper is not particularly limited, and can besuitably selected according to the object, and it is preferably 30 μm to500 μm, and more preferably 50 μm to 300 μm, and still more preferably100 μm to 250 μm. The basis weight of the raw paper is not particularlylimited, and can be suitably selected according to the object, and forexample, it is preferably from 50 g/m² to 250 g/m², and more preferablyfrom 100 g/m² to 200 g/m².

—Press Dry Treatment—

The press dry treatment is not particularly limited and may be suitablyselected according to the object, provided that it can heat and dry thepulp paper material while pressing it to soften paper fibers and allowthe fibers to come close to each other. For example, the pulp papermaterial is dehydrated using a manual paper-making machine and then itswater content before press dry treatment is adjusted to 30% to 70% usinga wet press apparatus or the like, thereby forming a sheet of raw paper.Then, at a drying temperature from 100° C. to 200° C., a press drytreatment is performed on the raw paper, specifically, on a side (of theraw paper whose water content is adjusted) to be formed with animage-recording layer.

Water content of the raw paper (wet paper) before the press dryingtreatment is preferably 30% to 70%, more preferably 40% to 60%.

The water content of the raw paper after the press drying treatment isnot particularly limited, and may be suitably selected according to theobject, preferably it is 10% or less, and more preferably 3% to 8%.

The drying temperature on the raw paper's side to be formed with theimage-recording layer is preferably from 100° C. to 200° C., morepreferably from 110° C. to 180° C. When the above drying temperature islower than 100° C., a sufficient amount of water does not evaporate andbonding among fibers becomes weak, which sometimes results inunfavorable paper force. When it is higher than 200° C., sizing propertyand planarity may become insufficient due to the relationship withadditives.

The pressure of the press dry treatment is preferably from 0.05 MPa to1.5 MPa, and more preferably from 0.05 MPa to 0.5 MPa.

The pressure of the press dry treatment less than 0.05 MPa may make theplanarity insufficient due to reduced fluidity of the resin, while morethan 1.5 MPa may cause partly uneven density.

The density of the raw paper after the press dry treatment is preferably0.85 g/cm³ to 1.05 g/cm³, and more preferably 0.9 g/cm³ to 1.05 g/cm³.The above density of the raw paper less than 0.85 g/cm³ may make theplanarity insufficient.

The apparatus with which the press dry treatment is performed is notparticularly limited and may be suitably selected according to theobject. For example, a press dry treatment apparatus 100 based onCondebelt drying technique as shown in FIG. 1 is preferable as anapparatus which is not incorporated in a production line and orientedtowards laboratory use.

The press dry treatment apparatus 100 has an upper plate 42, a lowerplate 43, a jacket 44 provided between the upper plate 42 and the lowerplate 43, and one or more other members when necessary.

Drying with the press dry treatment apparatus 100 is performed byplacing a sheet of wet paper (not shown) which has been prepared bydehydrating pulp paper material with a manual paper-making machine and awet press apparatus or the like in a jacket 44 which is impermeable toair; and thermally drying and pressuring the sheet with the upper plate42 and lower plate 43 the temperatures of which are each controlled byelectrically heated oil 47. During pressure drying, water vapor and thelike which are generated at the wet paper are removed by a vacuum tank49. Pressuring is performed by applying pressure to the lower plate 43with a pressing unit 48 using hydraulic oil 45. Further, during pressuredrying, cooling water 46 is configured to flow through the apparatus.

For example, STATIC CONDEBELT (manufactured by VALMET) which is a staticpress dry equipment may be used as one of such press dry treatmentapparatuses.

On the other hand, when the press dry treatment is to be incorporatedinto a production line so that it can be performed continuously, a pressdry treatment apparatus 200 as shown in FIG. 2 is preferable.

Referring to FIG. 2, the press dry treatment apparatus 200 includes afirst endless belt 38 and a second endless belt 39 which are impermeableto air and conduct heat well, a first set of turning rollers 51 and 52around which the first endless belt 38 is arranged to turn, and a secondset of turning rollers 53 and 54 around which the second endless belt 39is arranged to turn.

The first endless belt 38 and the second endless belt 39 are arranged insuch a way that they run part of the way parallel with each other sothat they form a drying zone between themselves.

A heating chamber 55 heats the first endless belt 38, and a coolingchamber 56 cools the second endless belt 39.

Then, dehydrated wet paper 40 and at least one fabric 41 which forms anendless loop are introduced between the first endless belt 38 and thesecond endless belt 39 in such a way that the dehydrated wet paper 40 isin contact with the heated first endless belt 38 and the fabric 41 ispositioned between the dehydrated wet paper 40 and both of the cooledsecond endless belt 39 and guide rollers and accordingly the wet paper40 is pressure dried.

The details of the press dry treatment apparatus 200 are described inJP-A No. 2000-500536.

According to this press dry treatment apparatus, it is possible toachieve a good press dry result more efficiently than with conventionalones.

By the press dry treatment described above, the sheet of raw paper hasbetter density, elasticity modulus, tensile strength, strength and thelike so as to provide an image-recording material support which isexcellent in dimension stability and planarity and with which curl isless likely to occur. Accordingly, by using the above image-recordingmaterial support, it is possible to provide high-quality images.

To a cast coat layer which is provided on the raw paper after the pressdry treatment, when necessary, a calender treatment by means of a supercalender and the like may be carried out.

—Calender Treatment—

The paper is preferred to be subjected to the calender treatment afterthe press dry treatment.

The calender treatment is not particularly limited, and can be suitablyselected according to the object. In this case, however, a hightemperature soft calender treatment is preferred, and temperature of thesurface of the metal roll is preferably 110° C. or more, more preferably150° C. or more, and still more preferably 250° C. or more. An upperlimit of the temperature is for example 300° C.

Carrying out the calender treatment can obtain paper having high gloss.

As described above, the paper under the present invention has highplanarity and excellent gloss, and can be used for various applications.Particularly, the paper is preferably to be used for the image-recordingmaterial support described below.

(Image-Recording Material Support)

Under the present invention, an image-recording material supportaccording to its first aspect comprises a paper which comprises a rawpaper. The paper satisfies at least one of the following conditions (i)and (ii): (i) the paper has an inner bonding strength of 160 mJ or morespecified in Japan Technical Association of the Pulp and Paper IndustryNo. 54, and an average center surface roughness on at least one face ofthe paper is 0.9 μm or less at a cutoff wavelength of 0.3 mm to 0.4 mm,and (ii) an Oken type smoothness S (second) on the at least one face ofthe paper, and a density ρ (g/cm³) of the paper satisfy an expressionS^(1/2)/ρ³≧15.

As described above, the image-recording material support according toits first aspect is preferably to be subjected to at least one of thepress dry treatment and the calender treatment.

Under the present invention, an image-recording material supportaccording to its second aspect comprises a raw paper subjected to apress dry treatment to thereby form a press-dried face; and a coatlayer. The coat layer is made by subjecting the press-dried face of theraw paper to a surface treatment using a member with a smooth surface.

Moreover, the image-recording material support according to its secondaspect comprises another layer, when necessary.

—Formation of Coat Layer and Transfer of Surface Appearance—

For formation of coat layer and transfer of surface appearance, a methodis proposed of abutting the coat layer to a smooth surface of a member,to thereby transfer the surface appearance. In this case, the smoothsurface of the member is preferred to be a mirror face of a metal drum.

The method for transferring the surface appearance of the smooth surfaceto the coat layer is not particularly limited, and can be suitablyselected according to the object. For example, a cast coat method ispreferable. In the cast coat method, a cast coating solution is to beapplied to the raw paper which was subjected to the press dry treatment,then, in a state that the entire coat layer or the surface of the coatlayer is wet or plastic, the coat layer is to be crimped to a heatedfinished surface of the metal cast drum. With this, drying the coatlayer and the photographing of the finished surface can besimultaneously achieved.

The cast coast method is not particularly limited, and can be suitablyselected according to the object, examples including wet cast method,gelatinization cast method, rewet cast method and the like. Each of theabove methods is common in that photographing of the surface appearanceof the cast drum with the mirror face can obtain a high-gloss surface ofthe coat layer. The above methods have the following characteristics,respectively, up to a process that the cast coating solution applied tothe raw paper is crimped to the cast drum.

In FIG. 3, the wet cast method (direct method) is shown. In a state thatthe cast coating solution applied to the raw paper (which was subjectedto the press dry treatment) is not dried at all, the cast coatingsolution is crimped to a cast drum 10 (with a mirror face), to therebytransfer the surface appearance of the cast drum 10.

In FIG. 4, the gelatinization cast method is shown. The cast coatingsolution applied to the raw paper (which was subjected to the press drytreatment) is treated with a coagulation liquid, then the cast coatingsolution is gelatinized (free from fluidity) and is crimped to the castdrum 10 (with the mirror face), to thereby transfer the surfaceappearance of the cast drum 10.

In FIG. 5, the rewet cast method is shown. The cast coating solutionapplied to the raw paper (which was subjected to the press drytreatment) is dried in advance, then a rewet liquid having a maincomponent of water is applied to a dried coat face to thereby make acoat material swelled or plasticized, then the cast coat liquid iscrimped to the cast drum 10 (with the mirror face) and is dried, tothereby obtain cast coat paper which is smooth and highly glossy.Compared with the wet cast method and the gelatinization cast method,the rewet cast method is good in that the productivity is high.

In each of the wet cast method, the gelatinization cast method and therewet cast method, the cast drum is the one that is made of metal havinga cylindrical outer periphery mirror-machined, and ordinarily is heatedat 80° C. to 150° C. for use.

The coat layer to be disposed at least a first face of the raw paperwhich was subjected to the press dry treatment is obtained by applyingthereto the cast coating solution (including at least a pigment and abinder) and drying it.

The pigment is not particularly limited, and can be suitably selectedaccording to the object. Examples of the pigments include silica,alumina, calcium carbonate, magnesium carbonate, barium sulfate,aluminum hydroxide, kaolin, talc, clay, titanium dioxide, zinc oxide,various plastic pigments and the like, to be used either alone or incombination of two ore more.

The binder is not particularly limited, and can be suitably selectedaccording to the object. Examples of the binder include starches such asoxidized starch, esterified starch and the like; cellulose derivativessuch as carboxymethyl cellulose, hydroxyethyl cellulose and the like;proteins such as gelatin, casein, soybean albumin and the like;polyvinyl alcohol, polyvinyl pyrrolidone, acrylic resin, styrene-acrylicresin, vinyl acetate resin, vinyl chloride resin, urea resin, urethaneresin, alkyd resin, polyester resin, polycarbonate resin,styrene-butadiene latex and derivatives thereof. The above binders canbe used either alone or in combination of two or more. Use of a pluraltypes of the binders in combination may have proper variations accordingto property of the cast coating solution, prescription, application ofthe cast coat paper and the like.

A content of the binder is preferably 1% by mass to 10% by mass (solidconversion) to the entire amount of the coating solution, and morepreferably 3% by mass to 8% by mass.

Blend ratio of the pigment to the binder (P/B=dry blend mass part numberof pigment/dry blend mass part number of binder) is not particularlylimited, and can be suitably selected according to the object,preferably 1.5 to 15, and more preferably 3 to 7. Greater blend ratiomay lose the smoothness.

To the cast coating solution, the following assistants can be appliedwhen necessary: known assistants such as pigment dispersant, waterholding agent, thickener, antifoaming agent, preservative, colorant,waterproof agent, wetting agent, plasticizer, fluorescent paint,ultraviolet absorber, oxidation inhibitor, cationic high molecularelectrolyte and the like.

Examples of coaters for the cast coating solution include blade coater,air knife coater, roll coater, comma coater (made by KobayashiEngineering Works, Ltd.), brush coater, squeeze coater, curtain oater,kiss coater, bar coater, gravure coater and the like.

The amount of the cast coating solution (solid conversion) is preferably2 g/m² to 50 g/m², more preferably 3 g/m² to 30 g/m².

Examples of the methods for drying the coat layer include air floatingdrier, infrared drier, cylinder drier and the like.

In the case that a cast coat layer is formed by the rewet cast method,examples of the additives of rewet liquids include ammonium salt,polyamide resin, phosphor compound such as hexametaphosphate, amidecompound, fluoride, zinc sulfate, calcium formate, and the like.

In the case that the cast coat layer is to be formed by the coagulationmethod, examples of coagulants added to the coagulation liquid includesalts such as formic acid, acetic acid, citric acid, tartaric acid,lactic acid, hydrochloric acid, sulfuric acid, carbonic acid withcalcium, zinc, magnesium, sodium, potassium, barium, lead, cadmium,ammonium, and the like; boric acids such as borax; and the like. Theabove coagulants can be used either alone or in combination of two ormore.

The cast coat layer can be formed on one side of the raw paper, or onboth sides of the raw paper. The number of cast coat layers is notlimited to one, instead, a multiple-layer structure is allowed.

The image-recording material support under the present invention is, asdescribed above, so constituted that the coat layer is formed at leaston the side (of the raw paper which was subjected to the press drytreatment) to be formed with the image-recording layer, and the coatlayer is allowed to abut on the smooth surface to thereby transfer thesurface appearance. With this, the image-recording material support isexcellent in surface smoothness and is extremely excellent in gloss.

The average center surface roughness (SRa) on the side (of theimage-recording material support) to be formed with the image-recordinglayer is preferably 0.5 μm or less at a cutoff wavelength of 5 mm to 6mm, more preferably 0.1 μm to 0.4 μm. The average center surfaceroughness (SRa) over 0.5 μm may cause an insufficient planarity afterthe coating.

Herein, the average center surface roughness (SRa) can be obtained byscanning three-dimensionally a plane having a certain roughness, andtherefore is different from an average center line roughness (Ra) thatcan be obtained by scanning a linear roughness of a plane. For example,SURFCOM 570A-3DF (made by Tokyo Seimitsu) can be used for measuring theaverage center surface roughness (SRa) at the cutoff wavelength of 5 mmto 6 mm, based on the following measuring condition and analysiscondition.

—Measuring Condition and Analysis Condition—

Scanning direction: MD direction of sample.

Measuring length: Machining paper direction (X-direction) 50 mm, andperpendicular direction (Y-direction) thereto 30 mm.

Measuring pitch: X-direction 0.1 mm, Y-direction 0.1 mm.

Scanning speed: 30 mm/sec.

Band pass filter: 5 mm to 6 mm.

In terms of surface smoothness and gloss of the image-recording materialsupport: specifically, 20% or more at 20-degree gloss is preferable, and40% or more at 20-degree gloss is more preferable. The gloss less than20% may cause an insufficient gloss after the image formation.

The above 20-degree gloss can be measured based on JIS Z8741.

In terms of waterproof of the image-recording material support:specifically, Cobb sizing water absorbency (30 sec) is preferred to be10 g/m² or less, more preferably 5 g/m² or less, and still morepreferably 4 g/m² or less.

The above Cobb sizing water absorbency can be obtained by measuring theamount of water absorbency when a pure water has a contact with a samplefor 30 seconds pursuant to JIS P8140.

(Image-Recording Material)

The image-recording material under the present invention includes atleast a support and an image-recording layer formed on the support. Theabove support is the image-recording material support under the presentinvention.

The image-recording material differs with the use and type thereof, andexamples include an electrophotographic material, heat sensitivematerial, inkjet-recording material, sublimation transfer material,silver salt photographic material, heat transfer material and the like.

<Electrophotographic Material>

An electrophotographic material includes an image-recording materialsupport and at least one toner image-receiving layer which is disposedon at least one surface of this support under the present invention.When necessary, the electrophotographic material may further includeother layers which may be suitably selected. Examples of the otherlayers include a surface protection layer, an intermediate layer, anunderlayer, a cushion layer, a static control (prevention) layer, areflection layer, a color tone adjusting layer, a storage propertyimprovement layer, an antistick layer, an anticurl layer, a smoothinglayer and the like. These layers may have a single-layer structure or alaminated structure.

[Toner Image-Receiving Layer]

The toner image-receiving layer receives a color toner or a black tonerand forms an image. The toner image-receiving layer has a function toreceive toner which forms an image from a developing drum or anintermediate transfer by (static) electricity or pressure in atransferring step, and to fix the image by heat or pressure in a fixingstep.

The material of the toner image-receiving layer contains at least apolymer, when necessary, and various additives to be added for improvingthermodynamic properties of the toner image-receiving layer. Examples ofthe additives include releasing agent, plasticizer, filler,cross-linking agent, charge control agent, emulsifier, dispersant andthe like.

—Polymer For Toner Image-Receiving Layer—

Polymer for toner image-receiving layer is not particularly limited, andcan be suitably selected according to the object, examples thereofincluding (1) polyolefin resin, (2) polystyrene resin, (3) acrylicresin, (4) polyvinyl acetate or derivatives thereof, (5) polyamideresin, (6) polyester resin, (7) polycarbonate resin, (8) polyether resin(or acetal resin), (9) other resins. The above polymers may be usedeither alone or in combination of two or more. Among the above, in termsof embedding of the toner, preferably used are styrene resin, acrylicresin, and polyester resin which have high coagulation energy.

Examples of (1) polyolefin resins include polyolefin resins such aspolyethylene, polypropylene and the like; copolymer resins of olefins(such as ethylene, propylene and the like) with other vinyl monomers;and the like. Examples of the above copolymer resins of olefins withother vinyl monomers include ethylene-vinyl acetate copolymer; anionomer resin which is a copolymer of olefins with acrylic acid ormethacrylic acid; and the like. Herein, examples of the derivatives ofthe polyolefin include chlorinated polyethylene, chlorosulfonatedpolyethylene and the like.

Examples of (2) polystyrene resins include polystyrene resin,styrene-isobutylene copolymer, acrylonitrile-styrene copolymer (ASresin), acrylonitrile-butadiene-styrene copolymer (ABS resin),polystyrene-maleic anhydride resin and the like.

Examples of (3) acrylic resins include polyacrylic acid or estersthereof, polymethacrylic acid or esters thereof, polyacrylonitrile,polyacrylamide and the like.

Examples of esters of polyacrylic acid include homopolymer or polytypiccopolymer of acrylic acid. Examples of esters of acrylic acid includemethyl acrylate, ethyl acrylate, acrylic acid n-butyl, isobutylacrylate, dodecyl acrylate, acrylic acid n-octyl, acrylic acid2-ethylhexyl, acrylic acid 2-chloroethyl, phenyl acrylate,α-chloroacrylic acid methyl and the like.

Examples of esters of polymethacrylic acid include homopolymer orpolytypic copolymer of methacrylic acid. Examples of esters ofmethacrylic acid include methyl methacrylate, ethyl methacrylate, butylmethacrylate and the like.

Examples of (4) polyvinyl acetates or derivatives thereof includepolyvinyl acetate and polyvinyl alcohol which is obtained by saponifyingpolyvinyl acetate, polyvinyl acetal resin obtained by reacting polyvinylalcohol with aldehyde (for example, formaldehyde, acetaldehyde,butylaldehyde and the like), and the like.

Examples of (5) polyamide resins include polycondensation of diaminewith dibasic acid such as 6-nylon, 6,6-nylon and the like.

(6) polyester resin is produced by polycondensation of acid compositionwith alcohol composition. The acid composition is not particularlylimited, and can be suitably selected according to the object. Examplesof (6) polyester resins include maleic acid, fumaric acid, citraconicacid, itaconic acid, glutaconic acid, phthalic acid, terephthalic acid,isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaicacid, malonic acid, n-dodecenyl succinate, isododecenyl succinate,n-dodecyl succinate, isododecyl succinate, n-octenyl succinate, n-octylsuccinate, isooctenyl succinate, isooctyl succinate, trimellitic acid,pyromellitic acid, acid anhydrides thereof, low alcohol esters thereof,and the like.

The above alcohol composition is not particularly limited, and can besuitably selected according to the object. Diatomic alcohol ispreferable. Examples of fatty series diols include ethylene glycol,diethylene glycol, triethylene glycol, 1,2-propylene glycol,1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropyleneglycol, polyethylene glycol, polypropylene glycol, polytetramethyleneglycol and the like. Examples of alkylene oxide adducts of bisphenol Ainclude polyoxypropylene, (2.2)-2,2-bis (4-hydroxyphenyl)propane,polyoxypropylene (3.3)-2,2-bis (4-hydroxyphenyl)propane, polyoxyethylene(2.0)-2,2-bis (4-hydroxyphenyl)propane, polyoxypropylene(2.0)-polyoxyethylene (2.0)-2,2-bis(4-hydroxyphenyl)propylene,polyoxypropylene (6)-2,2-bis(4-hydroxyphenyl)propane and the like.

A general example of (7) polycarbonate resin is polycarbonate esterwhich is obtained by bisphenol A and phosgene.

Examples of (8) polyether resins (or acetal resin) include polyetherresins such as polyethylene oxide, polypropylene oxide and the like;acetal resins such as polyoxymethylene as ring-opening polymerizationand the like; and the like.

Examples of (9) other resins include polyurethane resin of polyaddition.

As the polymer for the toner image-receiving layer, those satisfyingtoner image-receiving layer properties (to be described afterward) arepreferable in a state that the toner image-receiving layer is formed.Those satisfying the above properties alone are more preferable. Use oftwo or more resins with different toner image-receiving layer properties(to be described afterward) is also preferable.

As the polymer for the toner image-receiving layer, those having greatermolecular weight are preferable than the thermoplastic resin used forthe toner. The relative molecular weight is, however, not limited to theabove, in view of thermodynamic properties of the thermoplastic resinused for the toner relative to the polymer for the toner image-receivinglayer. For example, when the polymer for the toner image-receiving layeris higher in terms of softening temperature than the thermoplastic resinused for the toner, preferably, the molecular weight is equal or as thecase may be the polymer for the toner image-receiving layer has smallermolecular weight.

As the polymer for the toner image-receiving layer, it is preferable touse a mixture of resins which have the same composition and havedifferent average molecular weights from each other. Japanese PatentApplication Laid-Open (JP-A) No. 08-334915 discloses a preferablerelation, in terms of molecular weight, between the polymer for thetoner image-receiving layer and the thermoplastic resin used for thetoner.

In terms of distribution of molecular weights, the polymer for the tonerimage-receiving layer is preferably wider than the thermoplastic resinused for the toner.

Preferably, the polymer for the toner image-receiving layer hasproperties disclosed in JP-A No. 05-127413, JP-A No. 08-194394, JP-A No.08-334915, JP-A No. 08-334916, JP-A No. 09-171265 and JP-A No.10-221877.

The polymer for the toner image-receiving layer is excellent inenvironmental property and workability since no organic solvent isdischarged at coating-drying step (i). Many releasing agents such as waxare unlikely to be solved in solvent at room temperature, and are oftendispersed, prior to usage, in solvent (water and organic solvent). Waterdispersing form is more stable and is more adaptive to production steps.Moreover, an aqueous coating is more likely to cause bleeding of wax onthe surface in the process of coating-drying, thus making it easier toobtain the effect of the releasing agent (antioffset property, adhesiveresistance and the like). For the above reasons, aqueous resins such aswater-dispersible polymer, water-soluble polymer and the like arepreferably used.

The above aqueous resins, provided that they are either thewater-dispersible polymer or the water-soluble polymer, are notparticularly limited in terms of composition, bonding structure,molecular structure, molecular weight, molecular weight distribution,form and the like, and can be suitably selected according to the object.Examples of aqueous group of the above polymers include sulfonic group,hydroxyl group, carboxylic group, amino group, amide group, ether groupand the like.

The above water-dispersible polymer can be made, for example, bysuitably selecting from the following and combining two or more of them:i) resins made by dispersing in water the polymers for tonerimage-receiving layer numbered by (1) to (9) above, ii) emulsions madeby dispersing in water the polymers for toner image-receiving layernumbered by (1) to (9) above, iii) copolymer thereof, iv) mixturethereof, and v) cationic modified product.

The water-dispersible polymer can be suitably synthesized for use, orthose commercially available are usable. Examples of commercial productsof the water-dispersible polymers include polyester resins such asVylonal series by Toyobo Co., Ltd., Pesresin A series by Takamatsu Oil &Fat Co., Ltd., Tuftone UE series by Kao Corp., Nichigo Polyester WRseries by Nippon Synthetic Chemical Industry Co., Ltd., Elitel series byUnitika Ltd. and the like; and acrylic resins such as Hiros XE, KE, andPE series by Seiko Chemical Industries Co., Ltd., Jurymer ET series byNihon Junyaku Co., Ltd. and the like.

The water-dispersible emulsion can be any suitable emulsion thatpreferably has a volume-average particle diameter of 20 nm or more.Examples of such emulsions are water-dispersible polyurethane emulsions,water-dispersible polyester emulsions, chloroprene emulsions,styrene-butadiene emulsions, nitrile-butadiene emulsions, butadieneemulsions, vinyl chloride emulsions, vinylpyridine-styrene-butadieneemulsions, polybutene emulsions, polyethylene emulsions, vinyl acetateemulsions, ethylene-vinyl acetate emulsions, vinylidene chlorideemulsions, and methyl methacrylate-butadiene emulsions. Among them,water-dispersible polyester emulsions are preferred.

The water-dispersible polyester emulsions are preferablyself-dispersible aqueous polyester emulsions, of which self-dispersibleaqueous carboxyl-containing polyester emulsions are typically preferred.The “self-dispersible aqueous polyester emulsion” herein means anaqueous emulsion containing a polyester resin that is self-dispersiblein an aqueous solvent without the use of an emulsifier and the like. The“self-dispersible aqueous carboxyl-containing polyester emulsion” meansan aqueous emulsion containing a polyester that contains carboxyl groupsas hydrophilic groups and is self-dispersible in an aqueous solvent.

The self-dispersible aqueous polyester emulsion preferably satisfies thefollowing requirements (1) to (4). This type of polyester resin emulsionis self-dispersible requiring no surfactant, is low in moistureabsorbency even in an atmosphere at high humidity, exhibits lessdecrease in its softening point due to moisture and can thereby avoidoffset in image-fixing and failures due to adhesion between sheetsduring storage. The emulsion is water-based and is environmentallyfriendly and excellent in workability. In addition, the polyester resinused herein readily takes a molecular structure with high coagulationenergy. Accordingly, the resin has sufficient hardness (rigidity) duringits storage but is melted with low elasticity and low viscosity duringan image-fixing process for electrophotography, and the toner issufficiently embedded in the toner-image-receiving layer to thereby formimages having sufficiently high quality.

(1) The number-average molecular weight Mn is preferably from 5000 to10000 and more preferably from 5000 to 7000.

(2) The molecular weight distribution (Mw/Mn) is preferably 4 or less,and more preferably 3 or less, wherein Mw is the weight-averagemolecular weight.

(3) The glass transition temperature Tg is preferably from 40° C. to100° C. and more preferably from 50° C. to 80° C.

(4) The volume average particle diameter is preferably from 20 nm to 200nm and more preferably from 40 nm to 150 nm.

(5) The content of the water-dispersible emulsion in the toner-imagereceiving layer is preferably from 10 percent to 90 percent by weight,and more preferably from 10 percent to 70 percent by weight.

The water-soluble polymer is not particularly limited, provided that theweight average molecular weight (Mw) is 400,000 or less, and can besuitably selected according to the object. The water-soluble polymer canbe suitably synthesized for use, or commercially available productthereof can be used. Examples of the water-soluble polymers includepolyvinyl alcohol, carboxy-modified polyvinyl alcohol, carboxymethylcellulose, hydroxyethyl cellulose, cellulose sulfate, polyethyleneoxide, gelatin, cationic starch, casein, sodium polyacrylate, sodiumstyrene-maleic acid anhydride copolymer: styrene-maleic acid anhydridecopolymer), sodium polystyrene sulfonate and the like. Among the above,polyethylene oxide is preferable.

Examples of commercial products of water-soluble polymer include variousPlascoat products by Goo Chemical Co., Ltd., Finetex ES series byDainippon Ink and Chemicals Inc. and the like; and those ofwater-soluble acrylic resins include Jurymer AT series by Nihon JunyakuCo., Ltd., Finetex 6161 and K-96 by Dainippon Ink and Chemicals Inc.,Hiros NL-1189 and BH-997 by Seiko Chemical Industries Co., Ltd. and thelike.

Examples of the water-soluble resins are given on page 26 of ResearchDisclosure No. 17,643, page 651 of Research Disclosure No. 18,716, pp.873-874 of Research Disclosure No. 307,105, and JP-A No. 64-13546.

A content of the water-soluble polymer in the toner image-receivinglayer is not particularly limited, and can be suitably selectedaccording to the object, preferably 0.5 g/m² to 2 g/m².

The polymer for the toner image-receiving layer can be used incombination with other polymer materials, in this case, however, thepolymer for the toner image-receiving layer is to be greater in contentthan the other polymer materials.

In the toner image-receiving layer, the content of polymer for the tonerimage-receiving layer is preferably 10% by mass or more, more preferably30% by mass or more, still more preferably 50% by mass or over, andparticularly preferably 50% by mass to 90% by mass.

—Releasing Agent—

The releasing agent can be blended to the toner image-receiving layer inorder to prevent offset of the toner image-receiving layer. Varioustypes of the releasing agent can be used and may be suitably selectedaccording to the object as long as it is able to form a layer of thereleasing agent on a surface of the toner image-receiving layer by beingheated and melted at a fixing temperature so as to deposit and to remainon the surface of the toner image-receiving layer, and by being cooledand solidified so as to form a layer of the releasing agent, thereafter.

The releasing agent can be at least one of silicone compounds, fluorinecompounds, waxes, and matting agents.

The releasing agent may be a compound described in Kaitei—Wakkusu noseishitsu to ouyou “Properties and Applications of Wax (Revised)” bySaiwai Publishing, or in the Silicone Handbook published by THE NIKKANKOGYO SHIMBUN. Also, the silicone compounds, fluorine compounds and waxin the toners mentioned in Japanese Patent Application Publication(JP-B) No. 59-38581, Japanese Patent Application Publication (JP-B) No.04-32380, Japanese Patent (JP-B) No. 2838498, JP-B No. 2949558, JapanesePatent Application Laid-Open (JP-A) No. 50-117433, No. 52-52640, No.57-148755, No. 61-62056, No. 61-62057, No. 61-118760, and JP-A No.02-42451, No. 03-41465, No. 04-212175, No. 04-214570, No. 04-263267, No.05-34966, No. 05-119514, No. 06-59502, No. 06-161150, No. 06-175396, No.06-219040, No. 06-230600, No. 06-295093, No. 07-36210, No. 07-43940, No.07-56387, No. 07-56390, No. 07-64335, No. 07-199681, No. 07-223362, No.07-287413, No. 08-184992, No. 08-227180, No. 08-248671, No. 08-248799,No. 08-248801, No. 08-278663, No. 09-152739, No. 09-160278, No.09-185181, No. 09-319139, No. 09-319143, No. 10-20549, No. 10-48889, No.10-198069, No. 10-207116, No. 11-2917, No. 11-44969, No. 11-65156, No.11-73049 and No. 11-194542 may be used. These compounds can also be usedin combination of two or more.

Examples of the silicone compounds include silicone oil, siliconerubber, silicone fine-particle, silicone-modified resin, reactivesilicone compound and the like.

Such silicone oils include, for example, unmodified silicon oil,amino-modified silicone oil, carboxy-modified silicone oil,carbinol-modified silicone oil, vinyl-modified silicone oil,epoxy-modified silicone oil, polyether-modified silicone oil,silanol-modified silicone oil, methacrylic-modified silicone oil,mercapto-modified silicone oil, alcohol-modified silicone oil,alkyl-modified silicone oil, and fluorine-modified silicone oil.

Examples of the silicone-modified resins are silicone-modified resinsderived from olefinic resins, polyester resins, vinyl resins, polyamideresins, cellulose resins, phenoxy resins, vinyl chloride-vinyl acetateresins, urethane resins, acrylic resins, styrene-acrylic resins, orcopolymers comprising at least one of these constitutive monomers.

The fluorine compound is not particularly limited, and can be suitablyselected according to the object. Examples of the fluorine compoundsinclude fluorine oil, fluoro rubber, fluorine-modified resin, fluorinesulfonic acid compound, fluorosulfonic acid, fluorine acid compound orsalt thereof, inorganic fluoride and the like.

The above waxes are largely classified into two, that is, natural waxand synthetic wax.

The natural wax is preferably at least one wax selected from vegetablewax, animal wax, mineral wax, and petroleum wax, among which vegetablewax is particularly preferable. The natural wax is also preferably awater-dispersible wax, from the viewpoint of compatibility and the likewhen an aqueous resin is used as the polymer for the tonerimage-receiving layer.

The vegetable wax is not particularly limited, and can be suitablyselected from those known in the art. The vegetable wax may be acommercial product, or suitably synthesized.

Examples of the vegetable waxes include carnauba wax, castor oil,rapeseed oil, soybean oil, Japan tallow, cotton wax, rice wax, sugarcanewax, candellila wax, Japan wax, jojoba oil, and the like.

Examples of commercial product of the carnauba wax include EMUSTARAR-0413 from Nippon Seiro Co., Ltd., and Cellusol 524 from Chukyo YushiCo., Ltd, and the like.

Examples of commercial product of the castor oil include purified castoroil from Itoh Oil Chemicals Co., Ltd.

Of these, carnauba wax having a melting point of 70° C. to 95° C. isparticularly preferable from the viewpoint of providing anelectrophotographic image-receiving paper sheet which is excellent inantioffset properties, adhesive resistance, paper transportingproperties, gloss, is less likely to cause crack and splitting, and iscapable of forming high-quality image.

The animal wax is not particularly limited, and can be suitably selectedfrom those known in the art. Examples of the animal waxes include beeswax, lanolin, spermaceti, whale oil, wool wax and the like.

The mineral wax is not particularly limited, and can be suitablyselected from those known in the art. The mineral wax may be commercialproduct, or suitably synthesized.

Examples of the mineral waxes include montan wax, montan ester wax,ozokerite, ceresin and the like. Of these, montan wax having a meltingpoint of 70° C. to 95° C. is particularly preferable from the viewpointof providing an electrophotographic image-receiving paper sheet which isexcellent in antioffset properties, adhesive resistance, papertransporting properties, gloss, is less likely to cause crack andsplitting, and is capable of forming high-quality image.

The petroleum wax is not particularly limited, and can be suitablyselected from those known in the art. The petroleum wax may becommercial product, or suitably synthesized.

Examples of the petroleum waxes include paraffin wax, a microcrystallinewax, and petrolatum and the like.

A content of the natural wax in the toner image-receiving layer (asurface) is preferably 0.1 g/m² to 4 g/m², and more preferably 0.2 g/m²to 2 g/m².

When the content is less than 0.1 g/m², the antioffset properties andthe adhesive resistance may deteriorate. When the content is more than 4g/m², the quality of an image may deteriorate because of the excessiveamount of wax.

The melting point of the natural wax is preferably 70° C. to 95° C., andmore preferably 75° C. to 90° C., from the viewpoint of antioffsetproperties and paper transporting properties.

The synthetic waxes are classified into synthetic hydrocarbon, modifiedwax, hydrogenated wax, and other grease synthetic wax. The synthetic waxis preferably a water-dispersible wax, from the viewpoint ofcompatibility when an aqueous thermoplastic resin is used as thethermoplastic resin in the toner image-receiving layer.

Examples of the synthetic hydrocarbons include Fischertropsch wax,polyethylene wax and the like.

Examples of the grease synthetic waxes include an acid amide compound(specifically, stearic acid amide and the like), an acid imide compound(specifically, anhydrous phthalic acid imide and the like) and the like.

The modified wax is not particularly limited, and can be suitablyselected according to the object. Examples of the modified waxes includeamine-modified wax, acrylic acid-modified wax, fluorine-modified wax,olefin-modified wax, urethane wax, alcohol wax and the like.

The hydrogenated wax is not particularly limited, and can be suitablyselected according to the object. Examples of the hydrogenated waxesinclude cured castor oil, castor oil derivatives, stearic acid, lauricacid, myristic acid, palmitic acid, behenic acid, sebacic acid,undecylenic acid, heptyl acids, maleic acid, high grade maleic oils andthe like.

The matting agent can be selected from any known matting agents. Solidparticles used as the matting agent can be classified into inorganicparticles and organic particles. Specifically, the inorganic mattingagents may be oxides (for example, silicon dioxide, titanium oxide,magnesium oxide, and aluminum oxide), alkaline earth metal salts (forexample, barium sulfate, calcium carbonate, and magnesium sulfate),silver halides (for example, silver chloride, and silver bromide), glassand the like.

Examples of the inorganic matting agents can be found in West GermanPatent No. 2529321, the U.K. Patent Nos. 760775, 1260772, and the U.S.Pat. Nos. 1,201,905, 2,192,241, 3,053,662, 3,062,649, 3,257,206,3,322,555, 3,353,958, 3,370,951, 3,411,907, 3,437,484, 3,523,022,3,615,554, 3,635,714, 3,769,020, 4,021,245 and 4,029,504.

Materials of the organic matting agent include starch, cellulose ester(for example, cellulose-acetate propionate), cellulose ether (forexample, ethyl cellulose) and a synthetic resin. It is preferred thatthe synthetic resin is insoluble or difficult to become solved. Examplesof synthetic resins that are insoluble or of low solubility in waterinclude poly(meth)acrylates (for example, polyalkyl(meth)acrylate,polyalkoxyalkyl(meth)acrylate, polyglycidyl(meth)acrylate), poly(meth)acrylamide, polyvinyl ester (for example, polyvinyl acetate),polyacrylonitrile, polyolefins (for example, polyethylene), polystyrene,benzoguanamine resin, formaldehyde condensation polymer, epoxy resin,polyamide, polycarbonate, phenolic resin, polyvinyl carbazole,polyvinylidene chloride and the like.

Copolymers, that is, a combination of monomers used in the abovepolymers may also be used.

In the case of the copolymers, a small amount of hydrophilic repeatingunits may be included. Examples of monomers which constitute thesehydrophilic repeating units include acrylic acid, methacrylic acid,α,β-unsaturated dicarboxylic acid, hydroxyalkyl(meth)acrylate,sulfoalkyl(meth)acrylate, styrene sulfonic acid and the like.

Examples of the organic matting agents can be found in the U.K. PatentNo. 1055713, the U.S. Pat. Nos. 1,939,213, 2,221,873, 2,268,662,2,322,037, 2,376,005, 2,391,181, 2,701,245, 2,992,101, 3,079,257,3,262,782, 3,443,946, 3,516,832, 3,539,344, 3,591,379, 3,754,924 and3,767,448, and JP-A Nos. 49-106821, and 57-14835.

Also, two or more types of solid particles may be used in combination.The average particle size of the solid particles may suitably be, forexample, 1 μm to 100 μm, and is more preferably 4 μm to 30 μm. The usageamount of the solid particles may suitably be 0.01 g/m² to 0.5 g/m², andis more preferably 0.02 g/m² to 0.3 g/m².

The melting point (° C.) of the releasing agent is preferably 70° C. to95° C., and more preferably 75° C. to 90° C., from the viewpoint ofantioffset properties and paper transport properties.

The release agent under the present invention which is added to a tonerimage-receiving layer may also use derivatives, oxides, refinedproducts, or mixtures of these. These may also have reactivesubstituents.

The content of the releasing agent, based on the mass of the tonerimage-receiving layer, is preferably 0.1% by mass to 10% by mass, morepreferably 0.3% by mass to 8.0% by mass, and still more preferably 0.5%by mass to 5.0% by mass.

The content less than 0.1% by mass may make the antioffset property andadhesion resistance insufficient, while more than 10% by mass maydeteriorate the image quality due to too large an amount of releasingagent.

—Plasticizers—

The plasticizers known in the art may be used without any particularlimitation. These plasticizers have the effect of adjusting the fluidityor softening of the toner image-receiving layer due to one of heat andpressure during toner fixing.

The plasticizer may be selected by referring to Kagaku binran “ChemicalHandbook” (ed. The Chemical Society of Japan, Maruzen), Kasozai—Sonoriron to ouyou “Plasticizers—Theory and Application” (ed. Koichi Murai,Saiwai Shobo), Kasozai no kenkyu—jou “The Study of Plasticizers, Part 1”and Kasozai no kenkyu—ge “The Study of Plasticizers, Part 2” (ed.Polymer Chemistry Association), or Binran—Gomu purasuchikku haigouyakuhin “Handbook of Rubber and Plastics Blending Agents” (ed. RubberDigest Co.), or the like.

Examples of the plasticizers include esters (for example, phthalicesters, phosphate esters, aliphatic acid esters, abiethyne acid ester,abietic acid ester, sebacic acid esters, azelinic ester, benzoates,butylates, epoxy aliphatic acid esters, glycolic acid esters, propionicacid esters, trimellitic acid esters, citrates, sulfonates,carboxylates, succinic acid esters, maleates, fumaric acid esters,phthalic acid esters, stearic acid esters and the like); amides (forexample, aliphatic acid amides and sulfoamides and the like); ethers;alcohols; lactones; polyethyleneoxy; and the like (See JP-A Nos.59-83154, 59-178451, 59-178453, 59-178454, 59-178455, 59-178457,62-174754, 62-245253, 61-209444, 61-200538, 62-8145, 62-9348, 62-30247,62-136646, and 02-235694 and the like).

The above plasticizers can be mixed into a resin for use.

The plasticizers may be polymers having relatively low molecular weight.In this case, it is preferred that the molecular weight of theplasticizer is lower than the molecular weight of the binder resin to beplasticized. Preferably, plasticizers have a molecular weight of 15000or less, or more preferably 5000 or less. When a polymer plasticizer isused as the plasticizer, the kind of the polymer of the polymerplasticizer is preferably the same as that of the binder resin to beplasticized. For example, when the polyester resin is plasticized,polyester having low molecular weight is preferable. Further, oligomersmay also be used as plasticizers.

Apart from the compounds mentioned above, there are commercial productssuch as, for example, Adecasizer PN-170 and PN-1430 (from Asahi DenkaCo., Ltd.); PARAPLEX-G-25, G-30 and G40 (from C. P. Hall); and, rosinester (ester gum) 8 L-JA, ester R-95, pentalin 4851, FK 115, 4820, 830,Ruizol 28-JA, Picolastic A75, Picotex LC and Cristalex 3085 (from RikaHercules, Inc) and the like.

The plasticizer can be used as desired to relax stress and distortion(physical distortions such as elasticity and viscosity, and distortionsof mass balance in molecules, binder main chains or pendant portions)which are produced when toner particles are embedded in the tonerimage-receiving layer.

The plasticizer may be dispersed in micro in the toner image-receivinglayer. The plasticizer may also be dispersed in micro, in a state ofsea-island, in the toner image-receiving layer. The plasticizer maypresent in the toner image-receiving layer in a state of sufficientlymixed with other components such as binder or the like.

The content of plasticizer in the toner image-receiving layer ispreferably 0.001% by mass to 90% by mass, more preferably 0.1% by massto 60% by mass, and still more preferably 1% by mass to 40% by mass.

The plasticizer may be used for the purpose of adjusting slidability(improvement of transportability by reducing friction), improving fixingpart offset (release of toner or layer to the fixing part), adjustingcurl balance, adjusting charge control (formation of a tonerelectrostatic image), and the like.

—Colorant—

The colorant is not particularly limited, and can be suitably selectedaccording to the object. Examples of colorants include fluorescentwhitening agents, white pigments, colored pigments, dyes and the like.

The fluorescent whitening agent has absorption in the near-ultravioletregion, and is a compound which emits fluorescence at 400 nm to 500 nm.Various fluorescent whitening agents known in the art may be usedwithout any particular limitation. Examples of the fluorescent whiteningagents include the compounds described in The Chemistry of SyntheticDyes Volume V, Chapter 8 edited by K. VeenRataraman. The fluorescentwhitening agent can be suitably synthesized for use, or thosecommercially available are usable. Specific examples of the fluorescentwhitening agents include stilbene compounds, coumarin compounds,biphenyl compounds, benzo-oxazoline compounds, naphthalimide compounds,pyrazoline compounds, carbostyryl compounds and the like. Examples ofthe commercial fluorescent whitening agents include WHITEX PSN, PHR,HCS, PCS, and B (from Sumitomo Chemicals), UVITEX-OB (from Ciba-Geigy,Co., Ltd.), and the like.

The white pigment is not particularly limited, and can be suitablyselected from those known in the art according to the object. Examplesof the white pigments include the inorganic pigments such as titaniumoxide, calcium carbonate and the like.

The colored pigment is not particularly limited, and can be suitablyselected from those known in the art according to the object. Examplesof the colored pigments include various pigments described in JP-A No.6344653, azo pigments, polycyclic pigments, condensed polycyclicpigments, lake pigments, carbon black and the like.

Examples of the azo pigments include azo lakes (such as carmine 6B, red2B and the like), insoluble azo compounds (such as monoazo yellow,disazo yellow, pyrazolo orange, Balkan orange and the like), condensedazo pigments (such as chromophthal yellow and chromophthal red), and thelike.

Examples of the polycyclic pigments include phthalocyanines such ascopper phthalocyanine blue, copper phthalocyanine green, and the like.

Examples of the condensed polycyclic pigments include dioxazines (suchas dioxazine violet), isoindolinones (such as isoindolinone yellow),threne pigments, perylene pigments, perinon pigments, thioindigopigments, and the like.

Examples of the lake pigments include malachite green, rhodamine B,rhodamine G, Victoria blue B and the like.

Examples of the inorganic pigments include oxide (titanium dioxide, ironoxide red and the like), sulfate (settling barium sulfate and the like),carbonate (settling calcium carbonate and the like), silicate (hydroussilicate, silicic anhydride and the like), metal powder (aluminumpowder, bronze powder, zinc powder, chrome yellow, iron blue and thelike) and the like.

The above pigments can be used either alone or in combination of two ormore.

The dye is not particularly limited, and can be suitably selected fromthose known in the art according to the object. Examples of the dyesinclude anthraquinone compounds, azo compounds and the like. These canbe used either alone or in combination of two or more.

Examples of water-insoluble dyes include architecture dye, disperse dye,oil-soluble dye and the like.

Examples of the architecture dyes include vat dyes such as C. I. Vatviolet 1, C. I. Vat violet 2, C. I. Vat violet 9, C. I. Vat violet 13,C. I. Vat violet 21, C. I. Vat blue 1, C. I. Vat blue 3, C. I. Vat blue4, C. I. Vat blue 6, C. I. Vat blue 14, C. I. Vat blue 20, C. I. Vatblue 35 and the like. Examples of the disperse dyes include C. I.disperse violet 1, C. I. disperse violet 4, C. I. disperse violet 10, C.I. disperse blue 3, C. I. disperse blue 7, C. I. disperse blue 58 andthe like. Examples of the oil-soluble dyes include C. I. solvent violet13, C. I. solvent violet 14, C. I. solvent violet 21, C. I. solventviolet 27, C. I. solvent blue 11, C. I. solvent blue 12, C. I. solventblue 25, C. I. solvent blue 55 and the like.

Colored couplers used in silver halide photography may also bepreferably used.

A content of the colorant in the toner image-receiving layer (surface)is preferably 0.1 g/m² to 8 g/m², and more preferably 0.5 g/m² to 5g/m².

When the content of colorant is less than 0.1 g/m², the lighttransmittance in the toner image-receiving layer becomes high. When itis more than 8 g/m², handling becomes more difficult, due to crack andadhesive resistance.

Among the colorants, the amount of the added pigment is, based on themass of the thermoplastic resin constituting the toner image-receivinglayer, preferably 40% by mass, more preferably 30% by mass or less, andstill more preferably 20% by mass or less.

The filler may be an organic or inorganic filler. Reinforcers for binderresins, bulking agents and reinforcements known in the art may be used.The filler may be selected, referring to “Handbook of Rubber andPlastics Additives” (ed. Rubber Digest Co.), “Plastics BlendingAgents—Basics and Applications” (New Edition) (Taisei Co.), “The FillerHandbook” (Taisei Co.), or the like.

As the filler, various inorganic fillers or inorganic pigments can beused suitably. Examples of inorganic fillers or inorganic pigmentsinclude silica, alumina, titanium dioxide, zinc oxide, zirconium oxide,micaceous iron oxide, white lead, lead oxide, cobalt oxide, strontiumchromate, molybdenum pigments, smectite, magnesium oxide, calcium oxide,calcium carbonate, mullite and the like. Of these, silica and aluminaare particularly preferred. These may be used either alone, or incombination of two or more. It is preferred that the filler has a smallparticle diameter. When the particle diameter is large, the surface ofthe toner image-receiving layer tends to become rough.

Examples of the silicas include spherical silica and amorphous silica.The silica may be synthesized by the dry method, wet method or aerogelmethod. The surface of the hydrophobic silica particles may also betreated by trimethylsilyl groups or silicone. Colloidal silica ispreferred. The silica is preferably porous.

The alumina includes anhydrous alumina and hydrated alumina. Examples ofcrystallized anhydrous aluminas which may be used are α, β, γ, δ, ζ, η,θ, κ, ρ, or χ. Hydrated alumina is preferred to anhydrous alumina. Thehydrated alumina may be a monohydrate or trihydrate. Monohydratesinclude pseudo-boehmite, boehmite and diaspore. Trihydrates includegibbsite and bayerite. Porous alumina is preferred.

The alumina hydrate can be synthesized by the sol-gel method, in whichammonia is added to an aluminum salt solution to precipitate alumina, orby hydrolysis of an alkali aluminate. Anhydrous alumina can be obtainedby dehydrating alumina hydrate by the action of heat.

The amount of filler to be added is preferably from 5 parts by mass to2000 parts by mass relative to 100 parts by mass of the dry mass of thebinder of the toner image-receiving layer.

A cross-linking agent can be added in order to adjust the storagestability or thermoplastic properties of the toner image-receivinglayer. Examples of the cross-linking agents include compounds containingtwo or more reactive groups in the molecule, such as an epoxy group, anisocyanate group, an aldehyde group, an active halogen group, an activemethylene group, an acetylene group and other reactive groups known inthe art.

The cross-linking agent may also be a compound having two or more groupscapable of forming bonds such as hydrogen bonds, ionic bonds, coordinatebonds, or the like.

Examples of the cross-linking agents include a coupling agent for resin,curing agent, polymerizing agent, polymerization promoter, coagulant,film-forming agent, film-forming assistant, or the like. Examples of thecoupling agents include chlorosilanes, vinylsilanes, epoxysilanes,aminosilanes, alkoxyaluminum chelates, titanate coupling agents and thelike. The examples further include other agents known in the art such asthose mentioned in Binran—Gomu purasuchikkusu no haigou yakuhin“Handbook of Rubber and Plastics Additives” (ed. Rubber Digest Co.).

The charge control agent is preferably added to adjust toner transfer,adhesion or the like to the toner image-receiving layer, and to preventcharge adhesion of the toner image-receiving layer.

The charge control agent may, without limitation, be any charge controlagent known in the art. Examples of the charge control agents includesurfactants such as a cationic surfactant, an anionic surfactant, anamphoteric surfactant, a nonionic surfactant, or the like; polymerelectrolytes, conductive metal oxides; and the like. Examples includecationic charge inhibitors such as quaternary ammonium salts, polyaminederivatives, cation-modified polymethylmethacrylate, cation-modifiedpolystyrene, or the like; anionic charge inhibitors such as alkylphosphates, anionic polymers, or the like; and nonionic chargeinhibitors such as aliphatic ester, polyethylene oxide, or the like. Theexamples are not limited thereto, however.

When the toner has a negative charge, it is preferred that the chargecontrol agent blended with the toner image-receiving layer is, forexample, cationic or nonionic.

Examples of the conductive metal oxides include ZnO, TiO₂, SnO₂, Al₂O₃,In₂O₃, SiO₂, MgO, BaO, MoO₃ and the like. These conductive metal oxidesmay be used alone, or may be used in combination of two or more.Moreover, the conductive metal oxide may contain (dope) other elements.For example, ZnO may contain Al, In, or the like, TiO₂ may contain Nb,Ta, or the like, and SnO₂ may contain Sb, Nb, halogen elements, or thelike.

—Other Additives—

The materials used for the toner image-receiving layer may also containvarious additives to improve image stability when output, or to improvestability of the toner image-receiving layer itself. Examples of theadditives include various known antioxidants, age resistors, degradationinhibitors, ozone degradation inhibitors, ultraviolet ray absorbers,metal complexes, light stabilizers, preservatives, fungicide and thelike.

The antioxidant is not particularly limited, and can be suitablyselected according to the object. Examples of the antioxidants includechroman compounds, coumarane compounds, phenol compounds (for example,hindered phenols), hydroquinone derivatives, hindered amine derivatives,spiroindan compounds and the like. The antioxidants can be found in JP-ANo. 61-159644.

Examples of age resistors include those found in Binran—Gomupurasuchikku haigou yakuhin—kaitei dai 2 han “Handbook of Rubber andPlastics Additives, Second Edition” (1993, Rubber Digest Co.), pp.76-121.

The ultraviolet ray absorber is not particularly limited, and can besuitably selected according to the object. Examples of the ultravioletray absorbers include benzotriazol compounds (described in the U.S. Pat.No. 3,533,794), 4-thiazolidone compounds (described in the U.S. Pat. No.3,352,681), benzophenone compounds (described in JP-A No. 46-2784),ultraviolet ray absorbing polymers (described in JP-A No. 62-260152).

The metal complex is not particularly limited, and can be suitablyselected according to the object. Examples of the metal complexesinclude those described in U.S. Pat. Nos. 4,241,155, 4,245,018,4,254,195, JP-A Nos. 61-88256, 62-174741, 63-199248, 01-75568, 01-74272and the like.

The ultraviolet ray absorbers and light stabilizers found in Binran—Gomupurasuchikku haigou yakuhin—kaitei dai 2 han “Handbook of Rubber andPlastics Additives, Second Edition” (1993, Rubber Digest Co.), pp.122-137 are preferably used.

Additives for photography known in the art may also be added to thematerial used for the toner image-receiving layer as described above.Examples of the photographic additives can be found in the Journal ofResearch Disclosure (hereinafter referred to as RD) No. 17643 (December1978), No. 18716 (November 1979) and No. 307105 (November 1989). Therelevant sections are shown. TABLE 1 Type of additive RD17643 RD18716RD307105 1. Whitener p. 24 p. 648 right p. 868 column 2. Stabilizer pp.24-25 p. 649 right pp. 868-870 column 3. Light absorber pp. 25-26 p. 649right pp. 873 (Ultraviolet ray absorber) column 4. Colorant image p. 25p. 650 right p. 872 stabilizer column 5. Film hardener p. 26 p. 651 leftcolumn p. 874-875 6. Binder p. 26 p. 651 left column p. 873-874 7.Plasticizer, lubricant p. 27 p. 650 right p. 876 column 8. Auxiliaryapplication pp. 26-27 p. 650 right pp. 875-876 agent column (Surfactant)9. Antistatic agent p. 27 p. 650 right p. 876-877 column 10. Mattingagent pp. 878-879

The toner image-receiving layer under the present invention is formed byapplying with a wire coater and the like the coating solution(containing thermoplastic resin for the toner image-receiving layer) tothe support and by drying it. The minimum film-forming temperature (MFT)of the thermoplastic resin under the present invention is preferably theroom temperature or higher, from the viewpoint of pre-print storage, andpreferably 100° C. or lower, from the viewpoint of fixing tonerparticles.

The toner image-receiving layer under the present invention preferablyhas the application mass after drying in a range from 1 g/cm² to 20g/cm², more preferably 4 g/cm² to 15 g/cm².

Thickness of the toner image-receiving layer is not particularlylimited, and can be suitably selected according to the object. Forexample, the thickness is preferably from 1 μm to 50 μm, more preferablyfrom 1 μm to 30 μm, still more preferably 2 μm to 20 μm, andparticularly preferably 5 μm to 15 μm.

—Physical Properties of Toner Image-Receiving Layer—

The 180° separation strength of the toner image-receiving layer at thetemperature for fixing with the fixing member is preferably 0.1 N/25 mmor less, and more preferably 0.041 N/25 mm or less. The 180° separationstrength can be measured based on the method described in JIS K6887using the surface material of the fixing member.

It is preferred that the toner image-receiving layer has a high degreeof whiteness. This whiteness is measured by the method specified in JISP 8123, and is preferably 85% or more. It is preferred that the spectralreflectance is 85% or more in the wavelength range of 440 nm to 640 nm,and that the difference between the maximum spectral reflectance and theminimum spectral reflectance in this wavelength range is within 5%.Further, it is more preferred that the spectral reflectance is 85% ormore in the wavelength range from 400 nm to 700 nm, and that thedifference between the maximum spectral reflectance and the minimumspectral reflectance in the wavelength is within 5%.

Specifically, for the whiteness, the value of L* is preferably 80 ormore, more preferably 85 or more, and still more preferably 90 or morein a CIE 1976 (L*a*b*) color space. The color tint of the white color ispreferably as neutral as possible. Regarding the color tint of thewhiteness, the value of (a*)²+(b*)² is preferably 50 or less, morepreferably 18 or less, and still more preferably 5 or less in the(L*a*b*) space.

It is preferred that the toner image-receiving layer has a high surfacegloss after being formed. The 45° gloss luster is preferably 60 or more,more preferably 75 or more, and still more preferably 90 or more, overthe whole range from white where there is no toner, to black where toneris densed at maximum.

However, the gloss luster is preferably 110 or less. When it is morethan 110, the image has a metallic luster which is undesirable.

Gloss luster may be measured by JIS Z 8741.

It is preferred that the toner image-receiving layer has high smoothnessafter fixing. The arithmetic average roughness (Ra) is preferably 3 μmor less, more preferably 1 μm or less, and still more preferably 0.5 μmor less, over the whole range from white where there is no toner, toblack where toner is densed at maximum.

Arithmetic average roughness may be measured by JIS B 0601, JIS B 0651,and JIS B 0652.

It is preferred that the toner image-receiving layer has one of thefollowing physical properties, more preferred that the tonerimage-receiving layer has several of the following physical properties,and most preferred that the toner image-receiving layer has all of thefollowing physical properties.

(1) T_(m) (melting temperature of toner image-receiving layer) ispreferably 30° C. or more, and more preferably equal to or less thanT_(m) (melting temperature of toner)+20° C.

(2) The temperature at which the viscosity of the toner image-receivinglayer is 1×10⁵ cp is preferably 40° C. or higher, and more preferablylower than the corresponding temperature for the toner.

(3) At a fixing temperature of the toner image-receiving layer, thestorage elasticity modulus (G′) is preferably 1×10² Pa to 1×10⁵ Pa, theloss elasticity modulus (G″) is preferably from 1×10² Pa to 1×10⁵ Pa.

(4) The loss tangent (G″/G′), which is the ratio of the loss elasticitymodulus (G″) to the storage elasticity modulus (G′) at a fixingtemperature of the toner image-receiving layer, is preferably from 0.01to 10.

(5) The storage elasticity modulus (G′) at a fixing temperature of thetoner image-receiving layer is preferably from −50 to +2500, relative tothe storage elasticity modulus (G′) at a fixing temperature of thetoner.

(6) The inclination angle on the toner image-receiving layer of themolten toner is preferably 50° or less, and more preferably 40° or less.

The toner image-receiving layer preferably satisfies the physicalproperties described in Japanese Patent No. 2788358, and JP-A Nos.07-248637, 08-305067 and 10-239889.

It is preferred that the surface electrical resistance of the tonerimage-receiving layer is 1×10⁶ Ω/cm² to 1×10¹⁵ Ω/cm² (under conditionsof 25° C., 65% RH).

When the surface electrical resistance is less than 1×10⁶ Ω/cm², thetoner amount transferred to the toner image-receiving layer isinsufficient, and the density of the toner image obtained may be toolow. On the other hand, when the surface electrical resistance is morethan 1×10¹⁵ Ω/cm², more charge than necessary is produced duringtransfer. Therefore, toner is transferred insufficiently, image densityis low and static electricity develops, thus causing dust to adhereduring handling of the electrophotographic image-receiving paper sheet.Moreover in this case, misfeed, overfeed, discharge marks, tonertransfer dropout and the like may occur during the copying.

The surface electrical resistances are measured based on JIS K 6911. Thesample is left with air-conditioning for 8 hours or more at atemperature of 20° C. and the humidity of 65% for humidity adjustment.Measurements are made using an R8340 produced by Advantest Ltd., underthe same environmental conditions after giving an electric current for 1minute at an applied voltage of 100 V.

—Other Layers—

Other layers of the toner image-receiving layer may include, forexample, a surface protective layer, back layer, intermediate layer,contact improving layer, undercoat, cushion layer, charge control(inhibiting) layer, reflecting layer, tint adjusting layer,preservability improving layer, anti-adhering layer, anti-curl layer,smoothing layer and the like. These layers may have a single-layerstructure or may be formed of two or more layers.

The surface protective layer is formed on the surface of the tonerimage-receiving layer for the purpose of protecting the surface,improving preservability, improving handling property, giving writingproperty, improving machine passing property, giving antioffset propertyand the like of the electrophotographic image-receiving paper sheet. Thesurface protective layer may have a single-layer structure or may beformed of two or more layers. As a binder, various kinds ofthermoplastic resins, thermosetting resins and the like may be used forthe surface protective layer. Resins of the binder and the tonerimage-receiving layer are preferably of the same kind. In this case,however, the surface protective layer and the toner image-receivinglayer do not need to be the same in terms of thermodynamic property,electrostatic property and the like. Those properties can be optimized.

The surface protective layer can be blended with the various additivesdescribed above that are usable for the toner image-receiving layer.Particularly, the surface protective layer can be blended with thereleasing agent used under the present invention, and other additivessuch as matting agent and the like. Various known matting agents arenamed.

The top surface layer of the electrophotographic image-receiving papersheet (for example, the surface protective layer when formed) ispreferred to have compatibility with the toner in terms of fixationproperty. Specifically, the top surface layer preferably has a contactangle with the melted toner in a range from 0° to 40°.

The back layer of the electrophotographic image-receiving paper sheet ispreferably formed on an opposite side of the toner image-receiving layerwith respect to the support, for the purpose of giving a backface outputproperty, improving output image quality of the backface, improving curlbalance, improving machine passing property and the like.

Color of the back layer is not particularly limited. In the case ofboth-side output type image-receiving paper sheet forming the image alsoon the backface, however, the color of the back layer is also preferredto be white. Like the surface, the back layer is preferred to havewhiteness of 85% or more and spectral reflectance of 85% or more.

Moreover, for improving both-side output property, the back layer mayhave a structure same as that of the toner image-receiving layer side.The back layer may use the various kinds of additives as explainedabove. Examples of the blended additives include matting agent, chargecontrol agent and the like. The back layer may have a single-layerstructure or may be formed of two or more layers.

When a mold-releasing oil is used for a fixing roller and the like forpreventing offset during the fixing, the back layer may have oilabsorbing property.

In the electrophotographic image-receiving paper sheet, the abovecontact improving layer is preferred to be formed for improving thecontact of the support and the toner image-receiving layer. The contactimproving layer may be blended with various additives described above,particularly the cross-linking agent. Moreover, the electrophotographicimage-receiving paper sheet is preferred to have a cushion layer and thelike between the contact improving layer and the toner image-receivinglayer, for improving receptivity of the toner.

The intermediate layer may be formed, for example, between the supportand the contact improving layer, between the contact improving layer andthe cushion layer, between the cushion layer and the tonerimage-receiving layer, between the toner image-receiving layer and thepreservability improving layer and the like. In the case of theelectrophotographic image-receiving paper sheet that is formed with thesupport, the toner image-receiving layer, and the intermediate layer,the intermediate layer can be formed, for example, between the supportand the toner image-receiving layer.

<Toner>

The electrophotographic image-receiving paper sheet under the presentinvention is used by allowing the toner image-receiving layer to receivethe toner during printing or copying.

The toner includes at least biding resin and colorant, when necessary,releasing agent and the like.

—Toner's Binder Resin—

The binder resin is not particularly limited, and can be selected,according to the object, from those ordinarily used for the toner.Examples of the binder resin include vinyl monopolymer of: styrenes suchas styrene, parachlorostyrene, or the like; vinyl esters such as vinylnaphthalene, vinyl chloride, vinyl bromide, vinyl fluoride, vinylacetate, vinyl propioniate, vinyl benzoate, vinyl butyrate, or the like;methylene aliphatic carboxylates such as methyl acrylate, ethylacrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octylacrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methylchloroacrylate, methyl methacrylate, ethyl methacrylate, butyl acrylate,or the like; vinyl nitriles such as acryloniotrile, methacrylonitrile,acrylamide, or the like; vinyl ethers such as vinyl methyl ether, vinylethyl ether, vinyl isobutyl ether, or the like; N-vinyl compounds suchas N-vinyl pyrrole, N-vinylcarbazole, N-vinyl indole, N-vinylpyrrolidone, or the like; and vinyl carboxylic acids such as methacrylicacid, acrylic acid, cinnamic acid, or the like. These vinyl monomers maybe used either alone, or copolymers thereof may be used. Further,various polyesters may be used, and various waxes may be used incombination.

Among these resins, it is preferable to use a resin of the same type asthe resin used for the toner image receiving layer of the presentinvention.

—Toner's Colorant—

The colorant is not particularly limited, and can be selected accordingto the object from those used ordinarily for the toner. Examples of thecolorants include various kinds of pigments such as carbon black, chromeyellow, Hansa yellow, Benzidine Yellow, threne yellow, quinoline yellow,permanent orange GTR, pyrazolone orange, Balkan orange, watch young red,permanent red, brilliant carmine 3B, brilliant carmine 6B, dippon oilred, pyrazolone red, lithol red, rhodamine B lake, lake red C, RoseBengale, aniline blue, ultramarine blue, chalco oil blue, methylene bluechloride, phthalocyanine blue, phthalocyanine green, malachite greenoxalate and the like. Other examples include various kinds of dyes suchas acridine dyes, xanthene dyes, azo dyes, benzoquinone dyes, azinedyes, anthraquinone dyes, thioindigo dyes, dioxazine dyes, thiazinedyes, azomethine dyes, indigo dyes, phthalocyanine dyes, aniline blackdyes, polymethine dyes, triphenyl methane dyes, diphenyl methane dyes,thiazine dyes, thiazole dyes, xanthene dyes and the like.

The above colorants may be used alone or in combination of two or more.

A content of the colorant is not particularly limited, and can besuitably selected according to the object, preferably 2% by mass to 8%by mass. The content of the colorant less than 2% by mass may weakentinting strength, while more than 8% by mass may lose transmittance.

—Toner's Releasing Agent—

The releasing agent may be in principle any of the waxes known in theart. Polar waxes containing nitrogen such as highly crystallinepolyethylene wax having relatively low molecular weight, Fischertropschwax, amide wax, urethane wax, and the like are particularly effective.

For polyethylene wax, it is particularly effective when the molecularweight is 1000 or less, and is more preferable when the molecular weightis 300 to 1000.

Since the compounds containing urethane bonds tend to stay in a solidstate due to the strength of the coagulation force of the polar groupseven if the molecular weight is lower, and since the melting point maybe set higher in view of the molecular weight, such compounds aresuitable in general. The preferred molecular weight is 300 to 1000. Theraw materials may be selected from various combinations such as adiisocyanic acid compound with a mono-alcohol, a monoisocyanic acid witha mono-alcohol, dialcohol with mono-isocyanic acid, tri-alcohol with amonoisocyanic acid, and a triisocyanic acid compound with mono-alcohol.However, in order to prevent the molecular weight from becoming toolarge, it is preferable to combine a compound having multiple functionalgroups with another compound having one functional group, and it isimportant that the amount of functional groups be equivalent.

Examples of the monoisocyanic acid compounds include dodecyl isocyanate,phenyl isocyanate and derivatives thereof, naphthyl isocyanate, hexylisocyanate, benzil isocyanate, butyl isocyanate, allyl isocyanate, andthe like.

Examples of the diisocyanic acid compounds include tolylenediisocyanate, 4,4′ diphenylmethane diisocyanate, toluene diisocyanate,1,3-phenylene diisocyanate, hexamethylene diisocyanate,4-methyl-m-phenylene diisocyanate, isophorone diisocyanate, and thelike.

Examples of the monoalcohols include methanol, ethanol, propanol,butanol, pentanol, hexanol, heptanol, and the like.

Examples of the dialcohols include various glycols such as ethyleneglycol, diethylene glycol, triethylene glycol, trimethylene glycol, andthe like.

Examples of the trialcohols include trimethylol propane, triethylolpropane, trimethanol ethane, and the like.

Like an ordinary releasing agent, the above urethane compounds can bemixed with resin or colorant, to be used as mixed-pulverized type toner.When used for the toner of the emulsion polymerization melting method,the urethane compound is to be dispersed in water in combination withthe ion surfactant or high molecular electrolyte (such as high molecularacid or high molecular base), and then heated to the melting point ormore, then subjected to a strong shearing caused by homogenizer orpressure discharge type dispersing apparatus for forming fine-particles,to thereby prepare releasing agent particle-containing dispersing liquid(particle: 1 μm or less) which can be used in combination with the resinparticle-containing dispersing liquid, the colorant-containingdispersing liquid and the like.

—Other Components of Toner—

The toner can be blended with other components such as inner additive,charge control agent, inorganic fine-particle, and the like. Examples ofthe inner additives include metals such as ferrite, magnetite, reducediron, cobalt, nickel, manganese and the like; alloy; magnetic bodiessuch as compounds including the above metals; and the like.

Examples of charge control agents include those ordinarily used such asquaternary ammonium salts, nigrosine compounds, dyes made of complexes(such as aluminum, iron, chrome, and the like), triphenyl methanepigments, and the like. It is preferable that the charge control agentis unlikely to be soluble in water, from the view point of controllingion strength which may cause an effect on stability during coagulationor meting, and the viewpoint of reducing waste water pollutant.

Examples of the inorganic fine-particles include all ordinary outeradditives on the toner surface such as silica, alumina, titania, calciumcarbonate, magnesium carbonate, tricalcium phosphate and the like. Theabove particles are preferably used by dispersing with ion surfactant,high molecular acid, and high molecular base.

Surfactants may also be used for emulsion polymerization, seedpolymerization, pigment dispersion, resin particle dispersion, releasingagent dispersion, coagulation or stabilization thereof. For example, itis effective to use, in combination, anionic surfactants such assulfuric acid ester salts, sulfonic acid salts, phosphoric acid esters,soaps, or the like; cationic surfactants such as amine salts, quaternaryammonium salts, or the like; or non-ionic surfactants such aspolyethylene glycols, alkylphenol ethylene oxide adducts, polybasicalcohols, or the like. These may generally be dispersed by a rotaryshear homogenizer or a ball mill, sand mill, dyno mill, or the like, allof which contain the media.

When necessary, the toner may be added by an outer additive. Examples ofthe outer additives include inorganic particle or organic particle.Examples of the inorganic particles include SiO₂, TiO₂, Al₂O₃, CuO, ZnO,SnO₂, Fe₂O₃, MgO, BaO, CaO, K₂O, Na₂O, ZrO₂, CaO.SiO₂, K₂O.(TiO₂)_(n),Al₂O₃, 2SiO₂, CaCO₃, MgCO₃, BaSO₄, MgSO₄ and the like. Examples of theorganic particles include fatty acids or derivatives thereof, powders ofthe above meal salts and the like, resin particles (such as fluorineresin, polyethylene resin, acrylic resin and the like), and the like.

Average particle diameter of the above is preferably from 0.01 μm to 5μm, more preferably from 0.1 μm to 2 μm.

There is no particular limitation on the process of manufacturing thetoner, but it is preferably manufactured by a process comprising thesteps of (i) forming coagulation particles in a dispersion of resinparticles to manufacture a coagulation particle dispersion, (ii) addinga fine particle dispersion to the coagulation particle dispersion sothat the fine particles adhere to the coagulation particles, thusforming adhesion particles, and (iii) heating the adhesion particleswhich melt to form toner particles.

—Physical Properties of Toner—

The toner preferably has a volume average particle diameter of 0.5 μm to10 μm. Lower than the above range may cause a harmful effect on toner'shandling (supplying property, cleanability, fluidity and the like), andmay decrease particle productivity. Larger than the above range maycause harmful effect on image and resolution attributable togranulariness and transferability.

It is preferable that the toner under the present invention satisfiesthe above range of volume average particle diameter and has adistribution index of volume average particle diameter (GSDv) of 1.3 orless.

The ratio (GSDv/GSDn) of the distribution index of volume averageparticle diameter (GSDv) to a distribution index of number averageparticle diameter (GSDn) is preferably 0.95 or more.

It is preferable that the toner under the present invention satisfiesthe above range of volume average particle diameter and has an average(1.00 to 1.50) of configuration indexes given by the followingexpression.Configuration index=(π×L ²)/(4×S)(where L denotes the maximum length of toner particle, and S denotesprojected area of toner particle)

The toner satisfying the above conditions can bring about an effect onimage, particularly granulariness and resolution. Moreover in this case,dropout or blur which may be caused by transfer is unlikely to occur,and handling may be unlikely to be influenced even when the averageparticle diameter becomes small.

From the viewpoint of improving image quality and preventing offsetduring the fixing step, it is preferable that the toner in itself hasstorage elasticity modulus G′ (measured at angle frequency of 10rad/sec) of 1×10² Pa to 1×10⁵ Pa at 150° C.

<Silver Salt Photographic Material>

The silver salt photographic material has, for example, a configurationin which an image-recording layer which develops at least yellow,magenta, and cyan (YMC) is disposed on an image-recording materialsupport under the present invention. It is generally used in, forexample, silver halide photography in which an exposed and printedsilver halide photographic sheet is soaked in several treatment bathsone after another so as to perform color developing, bleaching andfixing, washing with water, and drying.

<Inkjet-Recording Material>

The inkjet-recording material includes, for example, acolorant-receiving layer disposed on an image-recording material supportunder the present invention, where the colorant-receiving layer iscapable of receiving a liquid ink such as an aqueous ink (using apigment or dye as the colorant), an oil ink and the like; a solid inkwhich is solid at room temperature and which is melted and liquefiedwhen used for a print; and the like.

<Heat Transfer Material>

The heat transfer material has, for example, a configuration in which atleast a heat-melting ink layer as an image-recording layer is disposedon an image-recording material support under the present invention. Itis generally used in, for example, a method in which a heat sensitivehead heats the heat-melting ink layer so as to melt and transfer the inkto a heat transfer sheet.

<Heat Sensitive Material>

The heat sensitive material has, for example, a configuration in whichat least a heat-coloring layer is disposed on an image-recordingmaterial support under the present invention. Examples thereof include,but are not limited to, heat sensitive material and the like used inthermo-autochrome method (TA method) in which a repetition of heating bya heat sensitive head and fixing by ultraviolet light forms an image.

<Sublimation Transfer Material>

The sublimation transfer material has, for example, a configuration inwhich at least an ink layer containing a heat-diffusion pigment(subliming pigment) is disposed on an image-recording material supportunder the present invention. It is generally used in, for example, asublimation transfer method in which a heat sensitive head heats an inklayer so as to transfer the heat-diffusion pigment to a sublimationtransfer sheet.

<Printing Paper>

The image-recording material support is preferably used as printingpaper. In this case, the support is preferred to have high mechanicalstrength since the ink is to be applied by means of a printing machine.

The raw materials used as the image-receiving material supportpreferably include filling material, softener, an inner additiveassistant for paper, and the like. The filling materials ordinarily usedare usable, whose examples including inorganic filling materials such asclay, firing clay, diatom earth, talc, kaolin, firing kaolin,delaminated kaolin, heavy calcium carbonate, soft calcium carbonate,magnesium carbonate, barium carbonate, titanium carbonate, zinc oxide,silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide,magnesium hydroxide, zinc hydroxide and the like; organic fillingmaterials such as urea-formalin resin, polystyrene resin, phenol resin,minor hollow particle, and the like; and the like. The above fillingmaterials may be used alone or in combination of two or more.

Examples of the inner additive assistants for paper-making include thoseconventionally used such as various kinds of yield promoters which arenonionic, cationic, and anionic; freeness promoter; paper forcepromoter; inner additive sizing agent; and the like. Specific examplesinclude basic aluminum compounds such as aluminum sulfate, aluminumchloride, sodium aluminate, basic aluminum chloride, basic poly(aluminumhydroxide)s; polyvalent metal compounds such as ferrous sulfate, ferricsulfate, and the like; water soluble high polymers such as starch,modified starch, polyacrylamide, urea resin, melamine resin, epoxyresin, polyamide resin, polyamine resin, polyamine, polyethylene imine,plant gum, polyvinyl alcohol, latex, polyethylene oxide, and the like;various compounds such as hydrophilic cross-linking agent polymerparticle dispersion, derivatives thereof, and modified product thereof;and the like. The above materials have several functions at the sametime as inner additive assistants for the paper-making.

Examples of materials having a remarkable function as inner sizing agentinclude alkyl ketene dimer compounds, alkenyl succinic anhydridecompound, styrene-acrylic compound, higher fatty acid compound,petroleum resin sizing agent, rosin sizing agent, and the like.

Other examples of the inner sizing agents include those for paper-makingsuch as dye, fluorescent whitening agent, pH regulator, defoaming agent,pitch control agent, slime control agent, and the like.

The printing paper is particularly preferable for offset printing paper.The other applications include relief printing, gravure printing,electrophotography, and the like.

The image-receiving material under the present invention hashigh-quality image and high gloss after image-forming, and causes asmall curl. Therefore, the image-receiving material under the presentinvention is preferably used for electrophotographic material, heatsensitive material, inkjet-recording material, sublimation transfermaterial, silver salt photographic material, heat transfer material, andthe like.

EXAMPLES

Hereafter, the present invention will be described by means of examples,but it will be understood that the invention is not construed as beinglimited thereto.

Example A-1 Preparation of Image-Recording Material Support

Broad-leaf (hardwood) tree bleached kraft pulp (LBKP) was beaten to aCanadian Standard Freeness (C. S. F.) of 280 ml using a disk refiner, tothereby prepare a pulp paper material having fiber length of 0.60 mm.

To this pulp paper material, the following additives were added based onthe pulp mass: cation starch 1.6% by mass, alkyl ketene dimer (AKD) 0.4%by mass, anion polyacrylamide 0.3% by mass, epoxidized fatty acid amide(EFA) 0.2% by mass, and polyamide polyamine epichlorohydrine 0.2% bymass. An alkyl part of the above alkyl ketene dimer originates from afatty acid having a main component of behenic acid. A fatty acid part ofthe epoxidized fatty acid amide originates from a fatty acid having amain component of behenic acid.

Thereafter, the pulp paper material was treated with a manualpaper-making machine to make wet paper having an absolute dry weight of140 g/m² and water content of 68%.

Both sides of the wet paper thus obtained were covered with filter paperand dehydrated using a wet press apparatus to adjust water content to47%.

The dehydrated wet paper was then dried with a press dry treatmentapparatus similar to the one shown in FIG. 1 (Static Condebelt availablefrom VALMET) to prepare raw paper with water content of 7.0% afterdrying. The press dry treatment was performed in a condition where thetemperature of an upper plate which was in contact with the raw paper onthe side (surface) where an image-recording layer was to be formed wasset at 150° C., the temperature of a lower plate which was in contactwith the raw paper on the side (backface) where no image-recording layerwas to be formed was set at 85° C., pressure was set at 0.4 MPa, anddrying time was set at 1 second.

The press-dry-treated raw paper was then calendered using a softcalender apparatus under the following conditions. The paper was passedthrough so that a metal roller having a surface temperature of 250° C.was in contact with the side (surface) of the raw paper on which animage-recording layer was to be formed, while allowing a resin roll onthe opposite side to have a set surface temperature of 40° C. The thusobtained paper as the image-recording material support has a density of0.96 g/cm³.

In this specification, including the claims, the terms “calender,”“calender apparatus,” and “calendering apparatus,” when referring to amachine used for calendering, mean the same.

Example A-2 to Example A-4 and Comparative Example A-1 to ComparativeExample A-6

Various conditions for the paper-making process were set as shown inTable 2. In the same manner as that in Example A-1, image-recordingmaterial supports of Example A-2 to Example A-4 and Comparative ExampleA-1 to Comparative Example A-6 were prepared. TABLE 2 Density Dry Pulp(g/cm³) Example A-1 Press dry LBKP = 100 0.87 Example A-2 Press dry LBKP= 100 0.98 Example A-3 Press dry LBKP/NBKP = 75/25 0.93 Example A-4Press dry LBKP/NBKP = 75/25 1.05 Comparative Press dry LBKP/NBKP = 25/750.87 Example A-1 Comparative Cylinder dry LBKP = 100 0.86 Example A-2Comparative Cylinder dry LBKP = 100 0.99 Example A-3 ComparativeCylinder dry LBKP/NBKP = 75/25 0.97 Example A-4 Comparative Cylinder dryLBKP/NBKP = 75/25 1.12 Example A-5 Comparative Cylinder dry LBKP/NBKP =50/50 0.97 Example A-6

Next, the thus obtained paper (image-recording material support) fromExample A-1 to Example A-4 and Comparative Example A-1 to ComparativeExample A-6 was subjected to an evaluation of inner bonding strength andplanarity. The results are shown in Table 3.

<Evaluation of Inner Bonding Strength>

Inner bonding strength was measured based on JAPAN TAPPI No. 54.

<Evaluation of Planarity>

A surface configuration measuring apparatus SURFCOM 570A-3DF (made byTokyo Seimitsu) was used for measuring the average center surfaceroughness (SRa) on the side (of the image-recording material support) tobe formed with the image-recording layer, at the cutoff wavelength of0.3 mm to 0.4 mm.

—Measuring Condition and Analysis Condition—

Scanning direction: MD direction of sample.

Measuring length: Machining paper direction (X-direction) 50 mm, andperpendicular direction (Y-direction) thereto 30 mm.

Measuring pitch: X-direction 0.1 mm, Y-direction 0.1 mm.

Scanning speed: 30 mm/sec.

Band pass filter: 0.3 mm to 0.4 mm

[Evaluation Standards]

A: Very good (SRa is 0.8 μm or less).

B: Good (SRa is 0.8 μm to less than 0.95 μm).

C: Mediocre (SRa is 0.95 μm to less than 1.1 μm).

D: Poor (SRa is 1.1 μm or more). TABLE 3 Inner bonding Smoothnessstrength Evaluation SRa (μm) Example A-1 218 mJ B 0.85 Example A-2 228mJ A 0.73 Example A-3 268 mJ B 0.84 Example A-4 270 mJ A 0.75Comparative 368 mJ C 0.97 Example A-1 Comparative 149 mJ C 0.99 ExampleA-2 Comparative 151 mJ B 0.91 Example A-3 Comparative 192 mJ C 1.09Example A-4 Comparative 198 mJ B 0.93 Example A-5 Comparative 240 mJ D1.21 Example A-6

Example A-5 to Example A-8 and Comparative Example A-7 to ComparativeExample A-12

The paper sheets (image-recording material supports) of Example A-1 toExample A-4 and Comparative Example A-1 to Comparative Example A-6 wereused for preparing the electrophotographic image-receiving paper sheets,respectively, of Example A-5 to Example A-8 and Comparative Example A-7to Comparative Example A-12, in the following methods.

—Titanium Dioxide Dispersion Solution—

The following components were blended and dispersed using an NBK-2non-bubbling kneader (available from Nippon Seiki) to prepare a titaniumdioxide dispersion solution (titanium dioxide pigment: 40% by mass).Titanium dioxide 40.0 g (TIPAQUE (registered Trademark) A-220, availablefrom Ishihara Sangyo Kaisha, Ltd.) Polyvinyl alcohol  2.0 g (PVA102,available from Kuraray Co., Ltd.) Ion exchange water 58.0 g—Preparation of Coating Solution for Toner Image-Receiving Layer—

The following components were mixed and stirred to prepare the coatingsolution for toner image-receiving layer. Aforementioned titaniumdioxide dispersion 15.5 g solution Carnauba wax dispersion solution 15.0g (Cellosol 524, available from Chukyo Yushi Co., Ltd.) Polyester resinaqueous dispersion 100.0 g (solids 30% by mass, KZA-7049, Unitika Ltd.)Thickener (Alcox E30, MEISEI CHEMICAL 2.0 g WORKS, LTD) Anionicsurfactant (AOT) 0.5 g Ion exchange water 80 ml

The thus obtained coating solution for toner image-receiving layer had aviscosity of 40 mPa·s and a surface tension of 34 mN/m.

—Preparation of Back Layer Coating Solution—

The following components were mixed and stirred to prepare a back layercoating solution. Acrylate resin aqueous dispersion 100.0 g (solids 30%by mass, High-Loss XBH-997L, available from Seiko Chemicals) Mattingagent 5.0 g (Techpolymer MBX-12, available from Sekisui Plastics Co.,Ltd.) Releasing agent (Hydrin D337, Chukyo Yushi Co., Ltd.) 10.0 gThickener (CMC) 2.0 g Anionic surfactant (AOT) 0.5 g Ion exchange water80 ml

The thus obtained back layer coating solution had a viscosity of 35mPa·s and a surface tension of 33 mN/m.

—Coating of Back Layer and Toner Image-Receiving Layer—

To the backface (namely, the side not to be formed with the tonerimage-receiving layer) of the image-recording material support of eachof Example A-1 to Example A-4 and Comparative Example A-1 to ComparativeExample A-6, the back layer coating solution was applied with a barcoater, such that the coating amount was 9 g/m² in dry mass, to therebyform the back layer. Then, to the surface of the image-recordingmaterial support, the coating solution for toner image-receiving layerwas applied with a bar coater in the same manner as the back layer, suchthat the coating amount was 12 g/m² in dry mass, to thereby form thetoner image-receiving layer. The content of the pigment in the tonerimage-receiving layer was 5% by mass, relative to the mass of thethermoplastic resin.

After the back layer coating solution and the toner image-receivinglayer coating solution were coated, they were dried by hot air, online.Airflow and temperature for drying were adjusted, so that both the backlayer and the toner image-receiving layer were dried within 2 minutesafter the coating. The point of dryness was determined when the surfacetemperature of the coating was equal to the wet-bulb temperature of theairflow for drying.

After the drying, a calender treatment was performed. A gloss calenderwas used for the calender treatment in which the temperature of a metalroller was maintained at 40° C. and a nip pressure was set at 14.7 kN/m²(15 kgf/cm²).

Each of the thus obtained electrophotographic image-receiving papersheets was cut to A4 size, and an image was printed thereon. The printerused here was a color laser printer (DocuColor 1250-PF) produced by FujiXerox Co., Ltd., excluding that a fixing belt apparatus 1 shown in FIG.6 was installed.

Specifically, in the fixing belt apparatus 1 as shown in FIG. 6, afixing belt 2 is suspended around a heating roller 3 and a tensionroller 5. A cleaning roller 6 is provided via the fixing belt 2 abovethe tension roller 5, and a pressurizing roller 4 is further providedvia the fixing belt 2 below the heating roller 3. In FIG. 6, startingfrom the right-hand side, the electrophotographic image-receiving papersheet carrying a toner latent image was introduced between the heatingroller 3 and the pressurizing roller 4, was fixed and then transportedon the fixing belt 2. Thereafter, in this process, theelectrophotographic image-receiving paper sheet was cooled by a coolingdevice 7, and the fixing belt 2 was finally cleaned by a cleaning roller6.

In the fixing belt apparatus 1, the transport speed at the fixing belt 2is 30 mm/sec, the nip pressure between the heating roller 3 and thepressurizing roller 4 was 0.2 MPa (2 kgf/cm²), and the temperature ofthe heating roller 3 was 150° C. which corresponded to the fixingtemperature. The temperature of the pressurizing roller 4 was set at120° C.

For each electrophotographic print thus obtained, image quality, glossand curl were evaluated in the following manner. The results are shownin Table 4.

<Evaluation of Image Quality>

The image quality of each electrophotographic print was visuallyobserved and was evaluated. The print with the best image quality wasassigned A, followed by B, C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Evaluation of Gloss>

The gloss of each electrophotographic print was visually observed andwas evaluated. The print with the best gloss was assigned A, followed byB, C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Evaluation of Curl>

The curl of each electrophotographic print was visually observed and wasevaluated. The print with the least curl was assigned A, followed by B,C, D and E on the following basis.

[Evaluation Standards]

A: No curl is found (Effective for high image quality recordingmaterial).

B: A small curl is found, but not problematical (Effective for highimage quality recording material).

C: Curl is found (Ineffective for high image quality recordingmaterial).

D: A large curl is found (Ineffective for high image quality recordingmaterial). TABLE 4 Image Curl Support Gloss quality property Example A-5Example A-1 A A A Example A-6 Example A-2 A A A Example A-7 Example A-3A A A Example A-8 Example A-4 A A B Comparative Comparative B C AExample A-7 Example A-1 Comparative Comparative C C B Example A-8Example A-2 Comparative Comparative C B C Example A-9 Example A-3Comparative Comparative C C B Example Example A-4 A-10 ComparativeComparative C B C Example Example A-5 A-11 Comparative Comparative C D AExample Example A-6 A-12

Example A-9 to Example A-12 and Comparative Example A-13 to ComparativeExample A-18 Preparation of Photographic Printing Paper

With the image-recording material supports prepared in Example A-1 toExample A-4 and Comparative Example A-1 to Comparative Example A-6,gelatin 0.1 g/m² was applied to the side (surface) to be formed with theimage-recording layer. The thus obtained gelatin coat face was furthercoated with the overlapping coatings in the following order of: i)silver halide gelatin emulsion layer (10 g/m²) for yellow coloringphotograph, ii) gelatin intermediate layer, iii) silver halide gelatinemulsion layer (10 g/m²) for magenta coloring photograph, iv) gelatinintermediate layer, v) silver halide gelatin emulsion layer (10 g/m²)for cyanogen coloring photograph, and vi) gelatin protective layer, tothereby prepare the photographic printing paper sheets, respectively, ofExample A-9 to Example A-12 and Comparative Example A-13 to ComparativeExample A-18.

The photographic printing papers thus obtained were exposed anddeveloped to prepare photographic prints. For each photographic print,surface smoothness (small-scale irregularity (1 mm or less) andlarge-scale irregularity (5 mm to 6 mm)) was evaluated in the followingmanner. The results are shown in Table 5.

<Surface Smoothness (Small-Scale Irregularity (1 mm or Less))>

The surface appearance of each photographic print was visually observedand was evaluated. The print with the best surface smoothness(small-scale irregularity (1 mm or less)) was assigned A, followed by B,C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Surface Smoothness (Large-Scale Irregularity (5 mm to 6 mm))>

The surface appearance of each photographic print was visually observedand was evaluated. The print with the best surface smoothness(large-scale irregularity (5 mm to 6 mm)) was assigned A, followed by B,C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).TABLE 5 Surface smoothness Small-scale Large-scale irregularityirregularity Support (1 mm or less) (5 mm to 6 mm) Example A-9 ExampleA-1 A A Example Example A-2 A A A-10 Example Example A-3 A A A-11Example Example A-4 A A A-12 Comparative Comparative A C Example ExampleA-1 A-13 Comparative Comparative D D Example Example A-2 A-14Comparative Comparative C B Example Example A-3 A-15 ComparativeComparative C C Example Example A-4 A-16 Comparative Comparative C BExample Example A-5 A-17 Comparative Comparative C D Example Example A-6A-18

Example B-1 Preparation of Image-Recording Material Support

Broad-leaf (hardwood) tree bleached kraft pulp (LBKP) was beaten to aCanadian Standard Freeness (C. S. F.) of 300 ml using a disk refiner, tothereby prepare a pulp paper material having fiber length of 0.60 mm.

To this pulp paper material, the following additives were added based onthe pulp mass: cation starch 1.2% by mass, alkyl ketene dimer (AKD) 0.5%by mass, anion polyacrylamide 0.2% by mass, epoxidized fatty acid amide(EFA) 0.2% by mass, and polyamide polyamine epichlorohydrine 0.3% bymass. An alkyl part of the above alkyl ketene dimer originates from afatty acid having a main component of behenic acid. A fatty acid part ofthe epoxidized fatty acid amide originates from a fatty acid having amain component of behenic acid.

Thereafter, the pulp paper material was treated with a manualpaper-making machine to make wet paper having an absolute dry weight of160 g/m² and water content of 68%.

Both sides of the wet paper were covered with filter paper anddehydrated using a wet press apparatus to adjust water content to 54%.

The dehydrated wet paper was then dried with a press dry treatmentapparatus similar to the one shown in FIG. 1 (Static Condebelt availablefrom VALMET) to prepare raw paper with water content of 7.0% afterdrying. The press dry treatment was performed in a condition where thetemperature of an upper plate which was in contact with the raw paper onthe side (surface) where an image-recording layer was to be formed wasset at 150° C., the temperature of a lower plate which was in contactwith the raw paper on the side (backface) where no image-recording layerwas to be formed was set at 85° C., pressure was set at 0.4 MPa, anddrying time was set at 1 second.

The press-dry-treated raw paper was then calendered using a softcalender apparatus under the following conditions. The paper was passedthrough so that a metal roller having a surface temperature of 250° C.was in contact with the side (surface) of the raw paper on which animage-recording layer was to be formed, while allowing a resin roll onthe opposite side to have a set surface temperature of 40° C.

With the image-recording material support, the Oken type smoothness S(second) based on JAPAN TAPPI No. 5 method B was measured on the side(surface) to be formed with the image-recording layer. The Oken typesmoothness S (second) was 251 seconds while a density ρ (g/cm³) of theimage-recording material support was 0.95 g/cm³. From the above Okentype smoothness S (second) and density ρ (g/cm³), the H index (obtainedby the expression S^(1/2)/ρ³) was measured to be 18.4. The results areshown in Table 6.

Example B-2 to Example B-4 and Comparative Example B-1 to ComparativeExample B-5

Various conditions for the paper-making process were set as shown inTable 6. In the same manner as that in Example B-1, image-recordingmaterial supports of Example B-2 to Example B-4 and Comparative ExampleB-1 to Comparative Example B-5 were prepared. TABLE 6 ρ Calen- (g/ H Dryder cm³) ρ³ S S^(1/2) index Example B-1 Press Calen- 0.95 0.86 251 15.818.4 dry dered Example B-2 Press Not calen- 0.87 0.66 151 12.3 18.7 drydered Example B-3 Press Calen- 0.98 0.94 295 17.2 18.3 dry dered ExampleB-4 Press Calen- 1.01 1.03 315 17.7 17.2 dry dered Comparative CylinderCalen- 0.81 0.53 50 7.07 13.3 Example B-1 dry dered Comparative CylinderCalen- 0.89 0.70 111 10.5 14.9 Example B-2 dry dered ComparativeCylinder Calen- 1.05 1.16 180 13.4 11.6 Example B-3 dry deredComparative Cylinder Calen- 1.12 1.40 250 15.8 11.2 Example B-4 drydered Comparative Cylinder Not calen- 0.72 0.37 17 4.12 11.0 Example B-5dry dered

Next, the thus obtained paper (image-recording material support) fromExample B-1 to Example B-4 and Comparative Example B-1 to ComparativeExample B-5 was subjected to an evaluation of gloss, surface planarity,and rigidity (stiffness). The results are shown in Table 7.

<Evaluation of Gloss>

The gloss of each image-recording material support was visually observedand was evaluated. The support with the best gloss was assigned A,followed by B, C, D and E on the following basis. The results are shownin Table 7.

[Evaluation Standards]

A: Very good.

B: Good.

C: Mediocre.

D: Poor.

E: Very poor.

<Evaluation of Surface Roughness>

A surface configuration measuring apparatus SURFCOM 570A-3DF (made byTokyo Seimitsu) was used for measuring the average center surfaceroughness (SRa) on the side (of the image-recording material support) tobe formed with the image-recording layer, at the cutoff wavelength of 5mm to 6 mm.

—Measuring Condition and Analysis Condition—

Scanning direction: MD direction of sample.

Measuring length: Machining paper direction (X-direction) 50 mm, andperpendicular direction (Y-direction) thereto 30 mm.

Measuring pitch: X-direction 0.1 mm, Y-direction 0.1 mm.

Scanning speed: 30 mm/sec.

Band pass filter: 5 mm to 6 mm

[Evaluation Standards]

A: Very good (SRa is 0.3 μm or less).

B: Good (SRa is less than 0.5 μm).

C: Mediocre (SRa is 0.5 μm to less than 1.0 μm).

D: Poor (SRa is 1.0 μm to less than 2.0 μm).

E: Very poor (SRa is 2.0 μm or more).

<Evaluation of Rigidity (Stiffness)>

The rigidity (stiffness) of the image-recording material support thusobtained was evaluated by hand-touch based on standard 1 to standard 5,where the greater the figure is the better the rigidity (stiffness) is.The results are shown in Table 7. TABLE 7 Surface Rigidity roughnessGloss (stiffness) Example B-1 A A 4 Example B-2 A B 4 Example B-3 A A 4Example B-4 A A 3 Comparative D D 4 Example B-1 Comparative D C 3Example B-2 Comparative B B 2 Example B-3 Comparative A A 1 Example B-4Comparative E D 4 Example B-5

Example B-5 to Example B-8 and Comparative Example B-6 to ComparativeExample B-10)

The paper sheets (image-recording material supports) of Example B-1 toExample B-4 and Comparative Example B-1 to Comparative Example B-5 wereused for preparing the electrophotographic image-receiving paper sheets,respectively, of Example B-5 to Example B-8 and Comparative Example B-6to Comparative Example B-10, in the following methods.

—Titanium Dioxide Dispersion Solution—

The following components were blended and dispersed using an NBK-2non-bubbling kneader (available from Nippon Seiki) to prepare a titaniumdioxide dispersion solution (titanium dioxide pigment: 40% by mass).Titanium dioxide 40.0 g (TIPAQUE (registered Trademark) A-220, availablefrom Ishihara Sangyo Kaisha, Ltd.) Polyvinyl alcohol  2.0 g (PVA102,available from Kuraray Co., Ltd.) Ion exchange water 58.0 g—Preparation of Coating Solution for Toner Image-Receiving Layer—

The following components were mixed and stirred to prepare the coatingsolution for toner image-receiving layer. Aforementioned titaniumdioxide dispersion 15.5 g solution Carnauba wax dispersion solution 15.0g (Cellosol 524, available from Chukyo Yushi Co., Ltd.) Polyester resinaqueous dispersion 100.0 g (solids 30% by mass, KZA-7049, Unitika Ltd.)Thickener (Alcox E30, MEISEI CHEMICAL 2.0 g WORKS, LTD) Anionicsurfactant (AOT) 0.5 g Ion exchange water 80 ml

The thus obtained coating solution for toner image-receiving layer had aviscosity of 40 mPa·s and a surface tension of 34 mN/m.

—Preparation of Back Layer Coating Solution—

The following components were mixed and stirred to prepare a back layercoating solution. Acrylate resin aqueous dispersion 100.0 g (solids 30%by mass, High-Loss XBH-997L, available from Seiko Chemicals) Mattingagent 5.0 g (Techpolymer MBX-12, available from Sekisui Plastics Co.,Ltd.) Releasing agent (Hydrin D337, Chukyo Yushi Co., Ltd.) 10.0 gThickener (CMC) 2.0 g Anionic surfactant (AOT) 0.5 g Ion exchange water80 ml

The thus obtained back layer coating solution had a viscosity of 35mPa·s and a surface tension of 33 mN/m.

—Coating of Back Layer and Toner Image-Receiving Layer—

To the backface (namely, the side not to be formed with the tonerimage-receiving layer) of the image-recording material support of eachof Example B-1 to Example B-4 and Comparative Example B-1 to ComparativeExample B-5, the back layer coating solution was applied with a barcoater, such that the coating amount was 9 g/m² in dry mass, to therebyform the back layer. Then, to the surface of the image-recordingmaterial support, the coating solution for toner image-receiving layerwas applied with a bar coater in the same manner as the back layer, suchthat the coating amount was 12 g/m² in dry mass, to thereby form thetoner image-receiving layer. The content of the pigment in the tonerimage-receiving layer was 5% by mass, relative to the mass of thethermoplastic resin.

After the back layer coating solution and the toner image-receivinglayer coating solution were coated, they were dried by hot air, online.Airflow and temperature for drying were adjusted, so that both the backlayer and the toner image-receiving layer were dried within 2 minutesafter the coating. The point of dryness was determined when the surfacetemperature of the coating was equal to the wet-bulb temperature of theairflow for drying.

After the drying, a calender treatment was performed. A gloss calenderwas used for the calender treatment in which the temperature of a metalroller was maintained at 40° C. and a nip pressure was set at 14.7 kN/m²(15 kgf/cm²).

Each of the thus obtained electrophotographic image-receiving papersheets was cut to A4 size, and an image was printed thereon. The printerused here was a color laser printer (DocuColor 1250-PF) produced by FujiXerox Co., Ltd., excluding that a fixing belt apparatus 1 shown in FIG.6 was installed.

Specifically, in the fixing belt apparatus 1 as shown in FIG. 6, afixing belt 2 is suspended around a heating roller 3 and a tensionroller 5. A cleaning roller 6 is provided via the fixing belt 2 abovethe tension roller 5, and a pressurizing roller 4 is further providedvia the fixing belt 2 below the heating roller 3. In FIG. 6, startingfrom the right-hand side, the electrophotographic image-receiving papersheet carrying a toner latent image was introduced between the heatingroller 3 and the pressurizing roller 4, was fixed and then transportedon the fixing belt 2. Thereafter, in this process, theelectrophotographic image-receiving paper sheet was cooled by a coolingdevice 7, and the fixing belt 2 was finally cleaned by a cleaning roller6.

In the fixing belt apparatus 1, the transport speed at the fixing belt 2is 30 mm/sec, the nip pressure between the heating roller 3 and thepressurizing roller 4 was 0.2 MPa (2 kgf/cm²), and the temperature ofthe heating roller 3 was 150° C. which corresponded to the fixingtemperature. The temperature of the pressurizing roller 4 was set at120° C.

For each electrophotographic print thus obtained, image quality, glossand rigidity (stiffness) were evaluated in the following manner. Theresults are shown in Table 8.

<Evaluation of Image Quality>

The image quality of each electrophotographic print was visuallyobserved and was evaluated. The print with the best image quality wasassigned A, followed by B, C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Evaluation of Gloss>

The gloss of each electrophotographic print was visually observed andwas evaluated. The print with the best gloss was assigned A, followed byB, C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Evaluation of Rigidity (Stiffness)>

The rigidity (stiffness) of each electrophotographic print thus obtainedwas evaluated by hand-touch based on standard 1 to standard 5, where thegreater the figure is the better the rigidity (stiffness) is. TABLE 8Image Rigidity Support Gloss quality (stiffness) Example B-5 Example B-1A A 4 Example B-6 Example B-2 A B 4 Example B-7 Example B-3 A A 4Example B-8 Example B-4 A A 4 Comparative Comparative D D 4 Example B-6Example B-1 Comparative Comparative C D 4 Example B-7 Example B-2Comparative Comparative C B 2 Example B-8 Example B-3 ComparativeComparative B A 2 Example B-9 Example B-4 Comparative Comparative D E 4Example Example B-5 B-10

Example B-9 to Example B-12 and Comparative Example B-11 to ComparativeExample B-15 Preparation of Photographic Printing Paper

With the image-recording material supports prepared in Example B-1 toExample B-4 and Comparative Example B-1 to Comparative Example B-5,gelatin 0.1 g/m² was applied to the side (surface) to be formed with theimage-recording layer. The thus obtained gelatin coat face was furthercoated with the overlapping coatings in the following order of: i)silver halide gelatin emulsion layer (10 g/m²) for yellow coloringphotograph, ii) gelatin intermediate layer, iii) silver halide gelatinemulsion layer (10 g/m²) for magenta coloring photograph, iv) gelatinintermediate layer, v) silver halide gelatin emulsion layer (10 g/m²)for cyanogen coloring photograph, and vi) gelatin protective layer, tothereby prepare the photographic printing paper sheets, respectively, ofExample B-9 to Example B-12 and Comparative Example B-11 to ComparativeExample B-15.

The photographic printing papers thus obtained were exposed anddeveloped to prepare photographic prints. For each photographic print,surface smoothness (small-scale irregularity (1 mm or less) andlarge-scale irregularity (5 mm to 6 mm)) was evaluated in the followingmanner. The results are shown in Table 9.

<Surface Smoothness (Small-Scale Irregularity (1 mm or Less))>

The surface appearance of each photographic print was visually observedand was evaluated. The print with the best surface smoothness(small-scale irregularity (1 mm or less)) was assigned A, followed by B,C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Surface Smoothness (Large-Scale Irregularity (5 mm to 6 mm))>

The surface appearance of each photographic print was visually observedand was evaluated. The print with the best surface smoothness(large-scale irregularity (5 mm to 6 mm)) was assigned A, followed by B,C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).TABLE 9 Surface smoothness Small-scale Large-scale irregularityirregularity Support (1 mm or less) (5 mm to 6 mm) Example B-9 ExampleB-1 A A Example Example B-2 A A B-10 Example Example B-3 A A B-11Example Example B-4 A A B-12 Comparative Comparative D D Example ExampleB-1 B-11 Comparative Comparative C C Example Example B-2 B-12Comparative Comparative C C Example Example B-3 B-13 ComparativeComparative C B Example Example B-4 B-14 Comparative Comparative D EExample Example B-5 B-15—Preparation of Image-Recording Material Support—

Broad-leaf (hardwood) tree bleached kraft pulp (LBKP) was beatens to aCanadian Standard Freeness (C. S. F.) of 300 ml using a disk refiner, tothereby prepare a pulp paper material having fiber length of 0.58 mm.

To this pulp paper material, the following additives were added based onthe pulp mass: cation starch 1.2% by mass, alkyl ketene dimer (AKD) 0.5%by mass, anion polyacrylamide 0.3% by mass, epoxidized fatty acid amide(EFA) 0.2% by mass, and polyamide polyamine epichlorohydrine 0.3% bymass. An alkyl part of the above alkyl ketene dimer originates from afatty acid having a main component of behenic acid. A fatty acid part ofthe epoxidized fatty acid amide originates from a fatty acid having amain component of behenic acid.

Thereafter, the pulp paper material was treated with a manualpaper-making machine to make wet paper having an absolute dry weight of160 g/m² and water content of 68%.

Both sides of the wet paper thus obtained were covered with filter paperand dehydrated using a wet press apparatus to adjust water content to50%.

The dehydrated wet paper was then dried with a press dry treatmentapparatus similar to the one shown in FIG. 1 (Static Condebelt availablefrom VALMET) to prepare raw paper with water content of 7.1% afterdrying. The press dry treatment was performed in a condition where thetemperature of an upper plate which was in contact with the raw paper onthe side (surface) where an image-recording layer was to be formed wasset at 160° C., the temperature of a lower plate which was in contactwith the raw paper on the side (backface) where no image-recording layerwas to be formed at 85° C., pressure was set at 0.45 MPa, and dryingtime was set at 1 second.

The press-dry-treated raw paper was then calendered using a machinecalender apparatus under the following conditions. The paper was passedthrough so that a metal roller having a surface temperature of 110° C.was in contact with the side (surface) of the raw paper on which animage-recording layer was to be formed. The thus obtained raw paper hasa density of 1.03 g/cm³.

—Cast Coating Solution A—

A cast coating solution A having solid density of 25% by mass wasprepared which solution including 100 mass part of an amorphous silica(Fine seal X-37 made by Tokuyama) as a pigment, and 20 mass part of apolyvinyl alcohol (PVA105 made by KURARAY CO., LTD.) as a binder.

—Cast Coating Solution B—

A cast coating solution B having solid density of 25% by mass wasprepared which solution including 100 mass part of an amorphous silica(Fine seal X-37 made by Tokuyama) as a pigment, and 10 mass part of apolyvinyl alcohol (PVA105 made by KURARAY CO., LTD.) as a binder.

—Cast Coating Solution C—

A cast coating solution C having solid density of 25% by mass wasprepared which solution including 100 mass part of an amorphous silica(Fine seal X-37 made by Tokuyama) as a pigment, and 65 mass part of apolyvinyl alcohol (PVA105 made by KURARAY CO., LTD.) as a binder.

Example C-1 Preparation of Image-Recording Material Support

A blade coater was used for coating a first face of a raw paper sheetwith a cast coating solution A such that a dried amount of the castcoast coating solution A becomes 15 g/m². Then, a coagulant(borax/water/surfactant (made by Dainippon Ink and ChemicalsInc.)=97.8/2/0.2) was applied for performing coagulation such that itssolid mass becomes 0.5 g/m². Then, while being in a wet state, the thusobtained coat surface is pressed to a cast drum having a surfacetemperature of 100° C., to thereby produce an image-recording materialsupport of Example C-1.

Example C-2 Preparation of Image-Recording Material Support

Example C-1 was repeated, except that the cast coating solution A wasreplaced with a cast coating solution B, to thereby produce animage-recording material support of Example C-2.

Example C-3 Preparation of Image-Recording Material Support

Example C-1 was repeated, except that the cast coating solution A wasreplaced with a cast coating solution C, to thereby produce animage-recording material support of Example C-3.

Comparative Example C-1 Preparation of Image-Recording Material Support

Example C-1 was repeated, except that the cast coat treatment using thecast coating solution A was not performed, to thereby produce animage-recording material support of Comparative Example C-1.

Comparative Example C-2 Preparation of Image-Recording Material Support

Example C-1 was repeated, except that the raw paper used was notsubjected to the press dry treatment, to thereby produce animage-recording material support of Comparative Example C-2.

Then, the supports of Example C-1 to Example C-3 and Comparative ExampleC-1 to Comparative Example C-2 were evaluated in terms of gloss andsurface roughness. The results are shown in Table 10.

<Evaluation of Gloss>

The gloss of each support was visually observed and was evaluated. Thesupport with the best gloss was assigned A, followed by B, C, D and E onthe following basis.

[Evaluation Standards]

A: Very good.

B: Good.

C: Mediocre.

D: Poor.

E: Very poor.

<Evaluation of Surface Smoothness>

A surface configuration measuring apparatus SURFCOM 570A-3DF (made byTokyo Seimitsu) was used for measuring the average center surfaceroughness (SRa) on the side (of the image-recording material support) tobe formed with the image-recording layer, at the cutoff wavelength of 5mm to 6 mm.

—Measuring Condition and Analysis Condition—

Scanning direction: MD direction of sample.

Measuring length: Machining paper direction (X-direction) 50 mm, andperpendicular direction (Y-direction) thereto 30 mm.

Measuring pitch: X-direction 0.1 mm, Y-direction 0.1 mm.

Scanning speed: 30 mm/sec.

Band pass filter: 5 mm to 6 mm

[Evaluation Standards]

A: Very good (SRa is 0.3 μm or less).

B: Good (SRa is less than 0.5 μm).

C: Mediocre (SRa is 0.5 μm to less than 1.0 μm).

D: Poor (SRa is 1.0 μm to less than 2.0 μm).

E: Very poor (SRa is 2.0 μm or more). TABLE 10 Surface Gloss smoothnessExample C-1 A A Example C-2 A B Example C-3 B A Comparative D D ExampleC-1 Comparative C D Example C-2

Example C-4 to Example C-6 and Comparative Example C-3 to ComparativeExample C-4

The paper sheets (image-recording material supports) of Example C-1 toExample C-3 and Comparative Example C-1 to Comparative Example C-2 wereused for preparing the electrophotographic image-receiving paper sheets,respectively, of Example C-4 to Example C-6 and Comparative Example C-3to Comparative Example C-4, in the following methods.

—Titanium Dioxide Dispersion Solution—

The following components were blended and dispersed using an NBK-2non-bubbling kneader (available from Nippon Seiki) to prepare a titaniumdioxide dispersion solution (titanium dioxide pigment: 40% by mass).Titanium dioxide 40.0 g (TIPAQUE (registered Trademark) A-220, availablefrom Ishihara Sangyo Kaisha, Ltd.) Polyvinyl alcohol  2.0 g (PVA102,available from Kuraray Co., Ltd.) Ion exchange water 58.0 g—Preparation of Coating Solution for Toner Image-Receiving Layer—

The following components were mixed and stirred to prepare the coatingsolution for toner image-receiving layer. Aforementioned titaniumdioxide dispersion 15.5 g solution Carnauba wax dispersion solution 15.0g (Cellosol 524, available from Chukyo Yushi Co., Ltd.) Polyester resinaqueous dispersion 100.0 g (solids 30% by mass, KZA-7049, Unitika Ltd.)Thickener (Alcox E30, MEISEI CHEMICAL 2.0 g WORKS, LTD) Anionicsurfactant (AOT) 0.5 g Ion exchange water 80 ml

The thus obtained coating solution for toner image-receiving layer had aviscosity of 40 mPa·s and a surface tension of 34 mN/m.

—Preparation of Back Layer Coating Solution—

The following components were mixed and stirred to prepare a back layercoating solution. Acrylate resin aqueous dispersion 100.0 g (solids 30%by mass, High-Loss XBH-997L, available from Seiko Chemicals) Mattingagent 5.0 g (Techpolymer MBX-12, available from Sekisui Plastics Co.,Ltd.) Releasing agent (Hydrin D337, Chukyo Yushi Co., Ltd.) 10.0 gThickener (CMC) 2.0 g Anionic surfactant (AOT) 0.5 g Ion exchange water80 ml

The thus obtained back layer coating solution had a viscosity of 35mPa·s and a surface tension of 33 mN/m.

—Coating of Back Layer and Toner Image-Receiving Layer—

To the backface (namely, the side not to be formed with the tonerimage-receiving layer) of the image-recording material support of eachof Example C-1 to Example C-3 and Comparative Example C-1 to ComparativeExample C-2, the back layer coating solution was applied with a barcoater, such that the coating amount was 9 g/m² in dry mass, to therebyform the back layer.

Then, to the surface of the image-recording material support, thecoating solution for toner image-receiving layer was applied with a barcoater in the same manner as the back layer, such that the coatingamount was 12 g/m² in dry mass, to thereby form the tonerimage-receiving layer. The content of the pigment in the tonerimage-receiving layer was 5% by mass, relative to the mass of thethermoplastic resin.

After the back layer coating solution and the toner image-receivinglayer coating solution were coated, they were dried by hot air, online.Airflow and temperature for drying were adjusted, so that both the backlayer and the toner image-receiving layer were dried within 2 minutesafter the coating. The point of dryness was determined when the surfacetemperature of the coating was equal to the wet-bulb temperature of theairflow for drying.

After the drying, a calender treatment was performed. A gloss calenderwas used for the calender treatment in which the temperature of a metalroller was maintained at 40° C. and a nip pressure was set at 14.7 kN/m²(15 kgf/cm²).

Each of the thus obtained electrophotographic image-receiving papersheets was cut to A4 size, and an image was printed thereon. The printerused here was a color laser printer (DocuColor 1250-PF) produced by FujiXerox Co., Ltd., excluding that the fixing belt apparatus 1 shown inFIG. 6 was installed.

Specifically, in the fixing belt apparatus 1 as shown in FIG. 6, afixing belt 2 is suspended around a heating roller 3 and a tensionroller 5. A cleaning roller 6 is provided via the fixing belt 2 abovethe tension roller 5, and a pressurizing roller 4 is further providedvia the fixing belt 2 below the heating roller 3. In FIG. 6, startingfrom the right-hand side, the electrophotographic image-receiving papersheet carrying a toner latent image was introduced between the heatingroller 3 and the pressurizing roller 4, was fixed and then transportedon the fixing belt 2. Thereafter, in this process, theelectrophotographic image-receiving paper sheet was cooled by a coolingdevice 7, and the fixing belt 2 was finally cleaned by a cleaning roller6.

In the fixing belt apparatus 1, the transport speed at the fixing belt 2is 30 mm/sec, the nip pressure between the heating roller 3 and thepressurizing roller 4 was 0.2 MPa (2 kgf/cm²), and the temperature ofthe heating roller 3 was 150° C. which corresponded to the fixingtemperature. The temperature of the pressurizing roller 4 was set at120° C.

For each electrophotographic print thus obtained, image quality andgloss were evaluated in the following manner. The results are shown inTable 11.

<Evaluation of Image Quality>

The image quality of each electrophotographic print was visuallyobserved and was evaluated. The print with the best image quality wasassigned A, followed by B, C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Evaluation of Gloss>

The gloss of each electrophotographic print was visually observed andwas evaluated. The print with the best gloss was assigned A, followed byB, C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).TABLE 11 Image Support Gloss quality Example C-4 Example C-1 A A ExampleC-5 Example C-2 A B Example C-6 Example C-3 B A Comparative ComparativeD D Example C-3 Example C-1 Comparative Comparative C D Example C-4Example C-2

Example C-7 to Example C-9 and Comparative Example C-5 to ComparativeExample C-6

—Preparation of Photographic Printing Paper—

With the image-recording material supports prepared in Example C-1 toExample C-3 and Comparative Example C-1 to Comparative Example C-2,gelatin 0.1 g/m² was applied to the side (surface) to be formed with theimage-recording layer. The thus obtained gelatin coat face was furthercoated with the overlapping coatings in the following order of: i)silver halide gelatin emulsion layer (10 g/m²) for yellow coloringphotograph, ii) gelatin intermediate layer, iii) silver halide gelatinemulsion layer (10 g/m²) for magenta coloring photograph, iv) gelatinintermediate layer, v) silver halide gelatin emulsion layer (10 g/m²)for cyanogen coloring photograph, and vi) gelatin protective layer, tothereby prepare the photographic printing paper sheets, respectively, ofExample C-7 to Example C-9 and Comparative Example C-5 to ComparativeExample C-6.

The photographic printing papers thus obtained were exposed anddeveloped to prepare photographic prints. For each photographic print,surface smoothness (small-scale irregularity (1 mm or less) andlarge-scale irregularity (5 mm to 6 mm)) was evaluated in the followingmanner. The results are shown in Table 12.

<Surface Smoothness (Small-Scale Irregularity (1 mm or Less))>

The surface appearance of each photographic print was visually observedand was evaluated. The print with the best surface smoothness(small-scale irregularity (1 mm or less)) was assigned A, followed by B,C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).

<Surface Smoothness (Large-Scale Irregularity (5 mm to 6 mm))>

The surface appearance of each photographic print was visually observedand was evaluated. The print with the best surface smoothness(large-scale irregularity (5 mm to 6 mm)) was assigned A, followed by B,C, D and E on the following basis.

[Evaluation Standards]

A: Very good (Effective for high image quality recording material).

B: Good (Effective for high image quality recording material).

C: Mediocre (Ineffective for high image quality recording material).

D: Poor (Ineffective for high image quality recording material).

E: Very poor (Ineffective for high image quality recording material).TABLE 12 Surface smoothness Small-scale Large-scale irregularityirregularity Support (1 mm or less) (5 mm to 6 mm) Example C-7 ExampleC-1 A A Example C-8 Example C-2 A B Example C-9 Example C-3 A AComparative Comparative D C Example C-5 Example C-1 ComparativeComparative C D Example C-6 Example C-2

Under the present invention, an image-recording material support can beprovided which has high planarity and excellent gloss. Moreover underthe present invention, an image-recording material can be provided whichallows an image-recording face after image-recording to havehigh-quality image and high gloss, and cause a small curl.

1.-23. (canceled)
 24. An image-recording material support, comprising: araw paper subjected to a press dry treatment; and a coat layer, whereinthe coat layer is formed by transferring a surface appearance of amember with a smooth surface to at least a face of the raw paper whichface is subjected to the press dry treatment, wherein the papersatisfies at least one of the following conditions (i) and (ii): (i) thepaper has an inner bonding strength, as defined in Japan TechnicalAssociation of the Pulp and Paper Industry No. 54, of 160 mJ or more,and an average center surface roughness on at least one face of thepaper is 0.9 μm or less at a cutoff wavelength of 0.3 mm to 0.4 mm, and(ii) an Oken type smoothness S (second) on the at least one face of thepaper, and a density ρ (g/cm³) of the paper satisfy an expressionS^(1/2)/ρ³≧5.
 25. The image-recording material support according toclaim 24, wherein the smooth surface of the member is a mirror face of asurface of a metal drum.
 26. The image-recording material supportaccording to claim 24, wherein the coat layer is a cast coat layer. 27.The image-recording material support according to claim 24, wherein theface subjected to the press dry treatment has an average center surfaceroughness of 0.5 μm or less at a cutoff wavelength of 5 mm to 6 mm. 28.An image-recording material, comprising: an image-recording materialsupport comprising a raw paper subjected to a press dry treatment; and acoat layer, wherein the coat layer is formed by transferring a surfaceappearance of a member with a smooth surface to at least a face of theraw paper which face is subjected to the press dry treatment; and animage-recording layer disposed on the image-recording material support,wherein the paper satisfies at least one of the following conditions (i)and (ii): (i) the paper has an inner bonding strength, as defined inJapan Technical Association of the Pulp and Paper Industry No. 54, of160 mJ or more, and an average center surface roughness on at least oneface of the paper is 0.9 μm or less at a cutoff wavelength of 0.3 mm to0.4 mm, and (ii) an Oken type smoothness S (second) on the at least oneface of the paper, and a density ρ (g/cm³) of the paper satisfy anexpression S^(1/2)/ρ³≧15.
 29. The image-recording material according toclaim 28, wherein the image-recording material is selected from thegroup consisting of an electrophotographic material, a heat sensitivematerial, an inkjet-recording material, a sublimation transfer material,a silver salt photographic material, and a heat transfer material. 30.The image-recording material according to claim 28, wherein the coatlayer is a cast coat layer.